add epiweeks to deps; fix failed n_elements messaging

forecasttools/daily_to_epiweekly.py

@@ -48,6 +48,12 @@ def daily_to_epiweekly(
     grouped_df = forecast_df.group_by(group_cols)
     # number of elements per group
     n_elements = grouped_df.agg(pl.count().alias("n_elements"))
+    problematic_trajectories = n_elements.filter(pl.col("n_elements") > 7)
+    if not problematic_trajectories.is_empty():
+        message = f"Problematic trajectories with more than 7 values per epiweek per year: {problematic_trajectories}"
+        raise ValueError(
+            f"At least one trajectory has more than 7 values for a given epiweek of a given year.\n{message}"
+        )
     # check if any week has more than 7 dates
     if not n_elements["n_elements"].to_numpy().max() <= 7:
         raise ValueError(

pyproject.toml

@@ -27,6 +27,7 @@ requests = "^2.32.3"
 polars = "^1.8.2"
 xarray = "^2024.9.0"
 matplotlib = "^3.9.2"
+epiweeks = "^2.3.0"
 
 [tool.poetry.group.dev.dependencies]
 pre-commit = "^3.8.0"