fix ligrec from pandas update

requirements.txt

@@ -6,12 +6,13 @@ dask[array]>=2021.02.0
 docrep>=0.3.1
 fsspec>=2021.11.0
 leidenalg>=0.8.2
+matplotlib>=3.3,!=3.6.1  # https://github.com/matplotlib/matplotlib/issues/24127
 matplotlib-scalebar>=0.8.0
 networkx>=2.6.0
 numba>=0.55.0,<0.56.0
 numpy>=1.21.6
 omnipath>=1.0.5
-pandas>=1.2.0
+pandas>=1.5.0
 Pillow>=8.0.0
 scanpy>=1.8.0
 scikit-image>=0.19

squidpy/pl/_ligrec.py

@@ -293,6 +293,10 @@ def get_dendrogram(adata: AnnData, linkage: str = "complete") -> Mapping[str, An
         means = means.T
 
     for cls, size in (pvals.groupby(level=0, axis=1)).size().to_dict().items():
+        size = np.unique(list(size.values()))
+        if len(size) != 1:
+            raise ValueError(f"Expected all groups to have the same number of interacting clusters, found `{size}`.")
+        size = size[0]
         label_ranges[cls] = (start, start + size - 1)
         start += size
     label_ranges = {k: label_ranges[k] for k in sorted(label_ranges.keys())}

tox.ini

@@ -71,6 +71,7 @@ filterwarnings =
     ignore:Auto-removal of grids by:DeprecationWarning:
     ignore:Support for passing numbers through unit converters:DeprecationWarning
     ignore:distutils Version classes are deprecated:DeprecationWarning
+    ignore::anndata.OldFormatWarning
 
 [coverage:run]
 branch = true