Added better error message for mismatch in cs and ax number (#185)

* Added better error message

* Updated changelog

* fix

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: timtreis

CHANGELOG.md

@@ -12,9 +12,9 @@ and this project adheres to [Semantic Versioning][].
 
 ### Added
 
--   Pushed `get_extent` functionality upstream to `spatialdata` (#162)
 -   Multiscale image handling: user can specify a scale, else the best scale is selected automatically given the figure size and dpi (#164)
 -   Large images are automatically rasterized to speed up performance (#164)
+-   Added better error message for mismatch in cs and ax number (#185)
 
 ### Fixed
 

src/spatialdata_plot/pl/basic.py

@@ -642,6 +642,15 @@ def show(
             elements=elements_to_be_rendered,
         )
 
+        # catch error in ruff-friendly way
+        if ax is not None:  # we'll generate matching number then
+            n_ax = 1 if isinstance(ax, Axes) else len(ax)
+            if len(coordinate_systems) != n_ax:
+                raise ValueError(
+                    f"Mismatch between number of matplotlib axes objects ({n_ax}) "
+                    f"and number of coordinate systems ({len(coordinate_systems)})."
+                )
+
         # set up canvas
         fig_params, scalebar_params = _prepare_params_plot(
             num_panels=len(coordinate_systems),