diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 00000000..bf2eaf07
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,15 @@
+{   "name": "Hydropandas",
+    // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+    "image": "mcr.microsoft.com/devcontainers/python:0-3.11",
+    "updateContentCommand": "chmod u+x .devcontainer/setup.sh && .devcontainer/setup.sh && chmod 666 .devcontainer/setup.sh",
+    "postAttachCommand": "code examples/01_groundwater_observations.ipynb", //alternative for customizations openFile -> https://github.com/orgs/community/discussions/58399#discussioncomment-6222762
+    "customizations": {
+      "vscode": {
+        "extensions": [
+          "github.codespaces",
+          "ms-python.python",
+          "ms-toolsai.jupyter"
+        ]
+      }
+    }
+  }
\ No newline at end of file
diff --git a/.devcontainer/setup.sh b/.devcontainer/setup.sh
new file mode 100644
index 00000000..55b00bca
--- /dev/null
+++ b/.devcontainer/setup.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+
+# Create model environments
+pip install -e .
\ No newline at end of file
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27f8fad9..4fbd5034 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,34 +11,25 @@ on:
 
 jobs:
   test:
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: true
       matrix:
         include:
           - name: Test suite with py312-ubuntu
             python: "3.12"
-            os: ubuntu-latest
             toxenv: py312
           - name: Test suite with py311-ubuntu
             python: "3.11"
-            os: ubuntu-latest
             toxenv: py311
           - name: Test suite with py310-ubuntu
             python: "3.10"
-            os: ubuntu-latest
             toxenv: py310
-          - name: Formatting with black + isort
-            python: "3.9"
-            os: ubuntu-latest
-            toxenv: format
-          - name: Linting with flake8 + ruff
-            python: "3.9"
-            os: ubuntu-latest
-            toxenv: lint
+          - name: Formatting and linting with ruff
+            python: "3.11"
+            toxenv: ruff
           - name: Test suite for notebooks and coverage
             python: "3.9"
-            os: ubuntu-latest
             toxenv: notebooks
 
     name: ${{ matrix.name }}
@@ -68,11 +59,4 @@ jobs:
         run: tox -e ${{ matrix.toxenv }} --notest
 
       - name: Test
-        run: tox -e ${{ matrix.toxenv }} --skip-pkg-install
-
-      - name: Run codacy-coverage-reporter
-        if: ${{ matrix.toxenv == 'notebooks' && github.repository == 'ArtesiaWater/hydropandas' && success() }}
-        uses: codacy/codacy-coverage-reporter-action@master
-        with:
-          project-token: ${{ secrets.CODACY_PROJECT_TOKEN }}
-          coverage-reports: coverage.xml
+        run: tox -e ${{ matrix.toxenv }} --skip-pkg-install
\ No newline at end of file
diff --git a/hydropandas/__init__.py b/hydropandas/__init__.py
index ac33cdf7..05b4f3f3 100644
--- a/hydropandas/__init__.py
+++ b/hydropandas/__init__.py
@@ -33,6 +33,7 @@
     WaterlvlObs,
     WaterQualityObs,
 )
+from .rcparams import rcParams
 from .version import __version__, show_versions
 
 logging.getLogger("hydropandas").addHandler(logging.NullHandler())
diff --git a/hydropandas/extensions/plots.py b/hydropandas/extensions/plots.py
index d25bdc0e..b33cb830 100644
--- a/hydropandas/extensions/plots.py
+++ b/hydropandas/extensions/plots.py
@@ -735,9 +735,9 @@ def series_per_group(
             if savefig:
                 if isinstance(by, list):
                     by_name = "-".join(by)
+                    groupname = "-".join(groupname)
                 else:
                     by_name = by
-                    groupname = "-".join(groupname)
                 if naming_method is None:
                     filename = f"series_by_{by_name}_group_{groupname}.png"
                 elif naming_method == "infer_name_monitoring_well":
diff --git a/hydropandas/io/bro.py b/hydropandas/io/bro.py
index 92322def..4f6499dd 100644
--- a/hydropandas/io/bro.py
+++ b/hydropandas/io/bro.py
@@ -5,6 +5,7 @@
 import json
 import logging
 import xml.etree.ElementTree
+from functools import lru_cache
 
 import numpy as np
 import pandas as pd
@@ -12,6 +13,7 @@
 from pyproj import Proj, Transformer
 from tqdm import tqdm
 
+from ..rcparams import rcParams
 from ..util import EPSG_28992
 
 logger = logging.getLogger(__name__)
@@ -422,8 +424,9 @@ def get_full_metadata_from_gmw(bro_id, tube_nr):
     return meta
 
 
-def get_tube_nrs_from_gmw(bro_id):
-    """returns all tube numbers from a groundwater monitoring well (gmw)
+@lru_cache()
+def _get_gmw_from_bro_id(bro_id, retries=0):
+    """get a gmw object from a bro_id
 
     Parameters
     ----------
@@ -432,31 +435,71 @@ def get_tube_nrs_from_gmw(bro_id):
 
     Returns
     -------
-    list of int
-        tube numbers
+    Element
+        xml reference to gmw object
+
+    Raises
+    ------
+    ValueError
+        if bro_id is invalid.
     """
 
+    if not bro_id.startswith("GMW"):
+        raise ValueError("can only get metadata if bro id starts with GMW")
+
     ns = {
         "dsgmw": "http://www.broservices.nl/xsd/dsgmw/1.1",
         "gmwcommon": "http://www.broservices.nl/xsd/gmwcommon/1.1",
         "gml": "http://www.opengis.net/gml/3.2",
     }
 
-    if not bro_id.startswith("GMW"):
-        raise ValueError("can only get metadata if bro id starts with GMW")
-
     url = f"https://publiek.broservices.nl/gm/gmw/v1/objects/{bro_id}"
     req = requests.get(url)
 
     # read results
     tree = xml.etree.ElementTree.fromstring(req.text)
 
-    # get gmw
     gmws = tree.findall(".//dsgmw:GMW_PO", ns)
     if len(gmws) != 1:
+        max_retries = rcParams["bro"]["max_retries"]
+        val_ind = req.text.find("valid")
+        valid = req.text[(val_ind + 9) : (val_ind + 14)]
+        if valid == "false" and retries < max_retries:
+            logger.debug(
+                f"got invalid response for {bro_id}, trying again {retries+1}/{max_retries}"
+            )
+            return _get_gmw_from_bro_id(bro_id, retries=retries + 1)
+        elif valid == "false":
+            raise Exception(
+                f"got invalid response for {bro_id} after trying {retries} times"
+            )
         raise (Exception("Only one gmw supported"))
     gmw = gmws[0]
 
+    return gmw
+
+
+def get_tube_nrs_from_gmw(bro_id):
+    """returns all tube numbers from a groundwater monitoring well (gmw)
+
+    Parameters
+    ----------
+    bro_id : str
+        bro id of groundwater monitoring well e.g. 'GMW000000036287'.
+
+    Returns
+    -------
+    list of int
+        tube numbers
+    """
+    ns = {
+        "dsgmw": "http://www.broservices.nl/xsd/dsgmw/1.1",
+        "gmwcommon": "http://www.broservices.nl/xsd/gmwcommon/1.1",
+        "gml": "http://www.opengis.net/gml/3.2",
+    }
+
+    gmw = _get_gmw_from_bro_id(bro_id)
+
     # get tube nrs
     tube_numbers = [
         int(tube.text)
@@ -490,28 +533,16 @@ def get_metadata_from_gmw(bro_id, tube_nr):
         dictionary with metadata.
 
     """
+    if not isinstance(tube_nr, int):
+        raise TypeError(f"expected integer got {type(tube_nr)}")
+
     ns = {
         "dsgmw": "http://www.broservices.nl/xsd/dsgmw/1.1",
         "gmwcommon": "http://www.broservices.nl/xsd/gmwcommon/1.1",
         "gml": "http://www.opengis.net/gml/3.2",
     }
 
-    if not bro_id.startswith("GMW"):
-        raise ValueError("can only get metadata if bro id starts with GMW")
-
-    if not isinstance(tube_nr, int):
-        raise TypeError(f"expected integer got {type(tube_nr)}")
-
-    url = f"https://publiek.broservices.nl/gm/gmw/v1/objects/{bro_id}"
-    req = requests.get(url)
-
-    # read results
-    tree = xml.etree.ElementTree.fromstring(req.text)
-
-    gmws = tree.findall(".//dsgmw:GMW_PO", ns)
-    if len(gmws) != 1:
-        raise (Exception("Only one gmw supported"))
-    gmw = gmws[0]
+    gmw = _get_gmw_from_bro_id(bro_id)
 
     meta = {"monitoring_well": bro_id, "tube_nr": tube_nr, "source": "BRO"}
 
diff --git a/hydropandas/io/knmi.py b/hydropandas/io/knmi.py
index e8568ffe..e78cf995 100644
--- a/hydropandas/io/knmi.py
+++ b/hydropandas/io/knmi.py
@@ -1023,7 +1023,7 @@ def get_knmi_daily_meteo_url(stn: int) -> Tuple[pd.DataFrame, Dict[str, Any]]:
 
 
 def read_knmi_file(
-    path: Union[str, Path, StringIO]
+    path: Union[str, Path, StringIO],
 ) -> Tuple[pd.DataFrame, Dict[str, Any]]:
     """read knmi daily meteo data from a file
 
diff --git a/hydropandas/io/pastas.py b/hydropandas/io/pastas.py
index 0ecba10a..f3af54cf 100644
--- a/hydropandas/io/pastas.py
+++ b/hydropandas/io/pastas.py
@@ -3,6 +3,7 @@
 
 @author: Artesia
 """
+
 import logging
 import numbers
 
diff --git a/hydropandas/obs_collection.py b/hydropandas/obs_collection.py
index 3e837dea..b7a5e1a8 100644
--- a/hydropandas/obs_collection.py
+++ b/hydropandas/obs_collection.py
@@ -812,6 +812,19 @@ def read_pastastore(
     )
 
 
+def _obscollection_constructor_with_fallback(*args, **kwargs):
+    """
+    A flexible constructor for ObsCollection._constructor, which falls back
+    to returning a DataFrame (if a certain operation does not preserve the
+    obs column). Copied from geopandas.
+    """
+    oc = ObsCollection(*args, **kwargs)
+    if "obs" not in oc.columns:
+        oc = pd.DataFrame(oc)
+
+    return oc
+
+
 class ObsCollection(pd.DataFrame):
     """Class for a collection of point observations.
 
@@ -871,7 +884,7 @@ def __init__(self, *args, **kwargs):
 
     @property
     def _constructor(self):
-        return ObsCollection
+        return _obscollection_constructor_with_fallback
 
     def _infer_otype(self):
         """Infer observation type from the obs column.
diff --git a/hydropandas/observation.py b/hydropandas/observation.py
index 9731dc38..71fcb0be 100644
--- a/hydropandas/observation.py
+++ b/hydropandas/observation.py
@@ -17,11 +17,11 @@
 import logging
 import os
 import warnings
+from _io import StringIO
 from typing import List, Optional
 
 import numpy as np
 import pandas as pd
-from _io import StringIO
 from pandas._config import get_option
 from pandas.api.types import is_numeric_dtype
 from pandas.io.formats import console
diff --git a/hydropandas/rcparams.py b/hydropandas/rcparams.py
new file mode 100644
index 00000000..8650953d
--- /dev/null
+++ b/hydropandas/rcparams.py
@@ -0,0 +1 @@
+rcParams = {"bro": {"max_retries": 5}}
diff --git a/hydropandas/version.py b/hydropandas/version.py
index b449fac5..4cc307b9 100644
--- a/hydropandas/version.py
+++ b/hydropandas/version.py
@@ -1,7 +1,7 @@
 from importlib import metadata
 from sys import version as os_version
 
-__version__ = "0.12.1"
+__version__ = "0.12.2"
 
 
 def show_versions():
diff --git a/pyproject.toml b/pyproject.toml
index 53aed96e..7892ed99 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,11 +65,10 @@ rtd = [
     "nbsphinx",
     "nbsphinx_link",
 ]
-linting = ["flake8", "ruff"]
-formatting = ["black[jupyter]", "isort"]
+ruffing = ["ruff"]
 pytesting = ["hydropandas[full,rtd]", "pytest>=7", "pytest-cov", "pytest-sugar"]
 coveraging = ["coverage"]
-dev = ["hydropandas[linting,formatting,pytesting]", "tox"]
+dev = ["hydropandas[ruffing,pytesting]", "tox"]
 
 [tool.setuptools]
 include-package-data = true
@@ -99,7 +98,7 @@ markers = ["slow: mark test as slow."]
 legacy_tox_ini = """
     [tox]
     requires = tox>=4
-    env_list = format, lint, notebooks, py{39, 310, 311, 312}
+    env_list = ruff, notebooks, py{39, 310, 311, 312}
 
     [testenv]
     description = run unit tests
@@ -114,19 +113,18 @@ legacy_tox_ini = """
             coverage run -m pytest tests
             coverage xml
 
-    [testenv:format]
-    description = run formatters
-    basepython = python3.9
-    extras = formatting
+    [testenv:ruff]
+    description = run ruff checks
+    basepython = python3.11
+    extras = ruffing
     commands =
-            black . --check --diff
-            isort . --check-only --diff
+            ruff check --extend-select I --preview
+            ruff format --check
 
-    [testenv:lint]
-    description = run linters
-    basepython = python3.9
-    extras = linting
+    [testenv:ruff_fix]
+    description = run ruff locally and fix issues
+    extras = ruffing
     commands =
-            flake8 . --max-line-length=88 --ignore=E741,W503
-            ruff check .
+            ruff check --extend-select I --fix
+            ruff format
 """
diff --git a/readme.md b/readme.md
index ac518779..41363b6e 100644
--- a/readme.md
+++ b/readme.md
@@ -2,7 +2,8 @@
 
 [![PyPi](https://img.shields.io/pypi/v/hydropandas.svg)](https://pypi.python.org/pypi/hydropandas)
 [![PyPi Supported Python Versions](https://img.shields.io/pypi/pyversions/hydropandas)](https://pypi.python.org/pypi/hydropandas)
-[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ArtesiaWater/hydropandas/master)
+[<img src="https://github.com/codespaces/badge.svg" height="20">](https://codespaces.new/ArtesiaWater/hydropandas?quickstart=1)
+
 
 [![hydropandas](https://github.com/ArtesiaWater/hydropandas/workflows/hydropandas/badge.svg)](https://github.com/ArtesiaWater/hydropandas/actions?query=workflow%3Ahydropandas)
 [![Codacy Badge](https://app.codacy.com/project/badge/Grade/c1b99f474bdc49b0a47e00e4e9f66c2f)](https://www.codacy.com/gh/ArtesiaWater/hydropandas/dashboard?utm_source=github.com&utm_medium=referral&utm_content=ArtesiaWater/hydropandas&utm_campaign=Badge_Grade)
diff --git a/tests/test_001_to_from.py b/tests/test_001_to_from.py
index b8511f70..bbcddde4 100644
--- a/tests/test_001_to_from.py
+++ b/tests/test_001_to_from.py
@@ -18,7 +18,7 @@ def test_bro_gld():
 
 def test_bro_gmn():
     # single observation
-    bro_id = "GMN000000000163"
+    bro_id = "GMN000000001084"  # 34 objects as per 2024-7-11
     hpd.read_bro(bro_id=bro_id, only_metadata=True)
 
 
@@ -31,7 +31,7 @@ def test_bro_extent():
 
 
 def test_bro_extent_too_big():
-    extent = (102395, 213550, 334331, 473920)  # to many observations in extent
+    extent = (102395, 213550, 334331, 473920)  # too many observations in extent
 
     with pytest.raises(HTTPError):
         hpd.read_bro(extent=extent, only_metadata=True)
diff --git a/tests/test_002_obs_objects.py b/tests/test_002_obs_objects.py
index 244c2729..0bc037a1 100644
--- a/tests/test_002_obs_objects.py
+++ b/tests/test_002_obs_objects.py
@@ -100,6 +100,17 @@ def test_copy_obs():
     assert "answer" in o3.meta.keys(), "copy method failed"
 
 
+def test_returns():
+    # check if a DataFrame is returned when an ObsCollection is sliced without the
+    # 'obs' column
+    oc = _obscollection_from_list()
+
+    assert isinstance(oc.loc[:, ["x", "y"]], pd.DataFrame)
+    assert not isinstance(oc.loc[:, ["x", "y"]], hpd.ObsCollection)
+
+    assert isinstance(oc.loc[:, ["x", "y", "obs"]], hpd.ObsCollection)
+
+
 def test_convert_waterlvl_groundwater_obs():
     # create WaterlvlObs
     df = pd.DataFrame(
diff --git a/tests/test_005_dino.py b/tests/test_005_dino.py
index 1ded9a79..3e03ecb3 100644
--- a/tests/test_005_dino.py
+++ b/tests/test_005_dino.py
@@ -18,12 +18,12 @@ def test_dino_csv_new_style():
 def test_dino_csv_duplicate_index():
     # contains 1 duplicate index 2019-11-19
     fname = "./tests/data/2019-Dino-test/Grondwaterstanden_Put/B22D0155001_1.csv"
-    measurements, meta = dino.read_dino_groundwater_csv(fname)
+    measurements, _ = dino.read_dino_groundwater_csv(fname)
 
     # check if measurements contains duplicate indices
     assert measurements.index.duplicated().any()
 
-    measurements, meta = dino.read_dino_groundwater_csv(
+    measurements, _ = dino.read_dino_groundwater_csv(
         fname, remove_duplicates=True, keep_dup="last"
     )
 
diff --git a/tests/test_006_knmi.py b/tests/test_006_knmi.py
index 79da5f56..70ef4628 100644
--- a/tests/test_006_knmi.py
+++ b/tests/test_006_knmi.py
@@ -147,8 +147,8 @@ def test_calculate_evaporation():
 
 
 def test_download_knmi_xy():
-    df1, meta1 = knmi.get_knmi_obs(meteo_var="RH", stn=344)
-    df2, meta2 = knmi.get_knmi_obs(meteo_var="RH", xy=(90600, 442800))
+    df1, _ = knmi.get_knmi_obs(meteo_var="RH", stn=344)
+    df2, _ = knmi.get_knmi_obs(meteo_var="RH", xy=(90600, 442800))
 
     assert df1.equals(df2), "Dataframes should be identical"
 
diff --git a/tests/test_013_lizard.py b/tests/test_013_lizard.py
index d7d65e2e..a24f6046 100644
--- a/tests/test_013_lizard.py
+++ b/tests/test_013_lizard.py
@@ -21,17 +21,14 @@ def test_codes():
 
 
 def test_many_tubed_well():
-
     oc = hpd.read_lizard(codes="EEWP004", tube_nr="all")
     assert not oc.empty
 
 
 def test_complex_well():
-
     oc = hpd.read_lizard(codes="BUWP014", tube_nr="all")
     assert not oc.empty
 
 
 def test_combine():
-
     hpd.GroundwaterObs.from_lizard("39F-0736", tube_nr=1, type_timeseries="combine")