diff --git a/src/pysimulators/datatypes.py b/src/pysimulators/datatypes.py
index 68d85c0..a59f33c 100644
--- a/src/pysimulators/datatypes.py
+++ b/src/pysimulators/datatypes.py
@@ -109,9 +109,7 @@ def __new__(
         ndmin=0,
         comm=None,
     ):
-
         if isinstance(data, str):
-
             if comm is None:
                 comm = MPI.COMM_SELF
 
@@ -641,7 +639,6 @@ def __new__(
         ndmin=0,
         comm=None,
     ):
-
         # get a new Map instance (or a subclass if subok is True)
         result = FitsArray.__new__(
             cls,
@@ -660,7 +657,6 @@ def __new__(
             result = result.view(cls)
 
         if isinstance(data, str):
-
             if comm is None:
                 comm = MPI.COMM_SELF
 
@@ -1022,7 +1018,6 @@ def __new__(
         ndmin=0,
         comm=None,
     ):
-
         # get a new Tod instance (or a subclass if subok is True)
         result = FitsArray.__new__(
             cls,
@@ -1045,7 +1040,6 @@ def __new__(
             mask = None
 
         if mask is None and isinstance(data, str):
-
             if comm is None:
                 comm = MPI.COMM_SELF
 
diff --git a/src/pysimulators/interfaces/madmap1.py b/src/pysimulators/interfaces/madmap1.py
index 6734d81..50ec186 100644
--- a/src/pysimulators/interfaces/madmap1.py
+++ b/src/pysimulators/interfaces/madmap1.py
@@ -43,7 +43,6 @@ def __init__(
         commin=MPI.COMM_WORLD,
         commout=MPI.COMM_WORLD,
     ):
-
         if commin.size > 1 or commout.size > 1:
             raise NotImplementedError(
                 'The parallelisation of the TOD is not implemented'
diff --git a/src/pysimulators/operators.py b/src/pysimulators/operators.py
index 329c325..d075e26 100644
--- a/src/pysimulators/operators.py
+++ b/src/pysimulators/operators.py
@@ -120,7 +120,6 @@ def block_diagonal(*partition_args, **keywords):
     def func(cls):
         @functools.wraps(cls.__init__)
         def partition_init(self, *args, **keywords):
-
             # get number of blocks through the partitionin keyword
             n1 = 0
             partitionin = None
@@ -611,7 +610,6 @@ class ProjectionBaseOperator(Operator):
     def __init__(
         self, units=None, derived_units=None, attrin={}, attrout={}, **keywords
     ):
-
         if units is None:
             units = ('', '')
         if derived_units is None:
diff --git a/src/pysimulators/quantities.py b/src/pysimulators/quantities.py
index 42f89f4..0686e1c 100644
--- a/src/pysimulators/quantities.py
+++ b/src/pysimulators/quantities.py
@@ -253,7 +253,6 @@ def __new__(
         subok=False,
         ndmin=0,
     ):
-
         data = np.asanyarray(data)
         if dtype is None and data.dtype.kind == 'i':
             dtype = float
@@ -685,7 +684,6 @@ def SI(self):
         ffast = Quantity(1.0, '')
         fslow = Quantity(1.0, '')
         for key, val in self._unit.items():
-
             # check if the unit is a local derived unit
             newfactor, broadcast = _check_du(self, key, val, self.derived_units)
 
diff --git a/tests/packedtables/test_packedtables.py b/tests/packedtables/test_packedtables.py
index 69cfcd0..e885551 100644
--- a/tests/packedtables/test_packedtables.py
+++ b/tests/packedtables/test_packedtables.py
@@ -42,7 +42,6 @@ def test_ndim1(shape):
     ],
 )
 def test_ndim2(shape, ndim):
-
     layout = PackedTable(shape, ndim=ndim)
     assert_equal(layout.ndim, ndim)
     assert_equal(layout.shape, shape)
@@ -463,7 +462,6 @@ def test_ordering3():
     ],
 )
 def test_ordering4(ordering, expected):
-
     layout = PackedTable((2, 3), ordering=ordering)
     assert_equal(layout._index, expected)
 
diff --git a/tests/packedtables/test_samplings.py b/tests/packedtables/test_samplings.py
index 852937f..626606f 100644
--- a/tests/packedtables/test_samplings.py
+++ b/tests/packedtables/test_samplings.py
@@ -10,7 +10,6 @@
 @pytest.mark.parametrize('fmt', [lambda ra: ((ra,), {}), lambda ra: ((), {'ra': ra})])
 @pytest.mark.parametrize('ra', [1.0, (1.0,), [1.0], np.ones(10), np.ones((2, 3))])
 def test_coords_ra(fmt, ra):
-
     args, keywords = fmt(ra)
     if len(args) > 0 and isscalarlike(args[0]):
         p = SamplingEquatorial(*args, **keywords)
diff --git a/tests/test_datatypes.py b/tests/test_datatypes.py
index 65ef210..50a803e 100644
--- a/tests/test_datatypes.py
+++ b/tests/test_datatypes.py
@@ -112,7 +112,6 @@ def test_input3(type_):
     ],
 )
 def test_view(type_, attrs):
-
     data = np.ones((2, 4)).view(type_)
     for attr in attrs:
         assert hasattr(data, attr)
diff --git a/tests/test_healpy.py b/tests/test_healpy.py
index bc690ba..ab35d79 100644
--- a/tests/test_healpy.py
+++ b/tests/test_healpy.py
@@ -32,7 +32,6 @@
 )
 @pytest.mark.parametrize('nest', [False, True])
 def test_cartesian_healpix(vec, shape, nest):
-
     c2h = Cartesian2HealpixOperator(NSIDE, nest=nest)
     h2c = Healpix2CartesianOperator(NSIDE, nest=nest)
     a = h2c(c2h(vec))
diff --git a/tests/test_operators.py b/tests/test_operators.py
index 98268aa..4e72e45 100644
--- a/tests/test_operators.py
+++ b/tests/test_operators.py
@@ -193,7 +193,6 @@ def ref_blackbody(w, T):
 
 
 def test_blackbody_scalar():
-
     w = np.arange(90.0, 111) * 1e-6
     T = 15.0
     flux = ref_blackbody(w, T) / ref_blackbody(100e-6, T)