In recent versions of matplotlib, _contour seems to be missing

[anders-kiaer]

Related to #1237 and

webviz-subsurface/webviz_subsurface/plugins/_co2_leakage/_utilities/plume_extent.py

Lines 8 to 18 in efa2852

	MISSING_DEPENDENCIES = False
	try:
	import shapely.geometry
	# Use _contour from MPL. Under the hood, this is the same functionality pyplot is
	# using. Direct use is implemented (instead of pyplot.contour directly) to avoid the
	# overhead related to figure/axis creation in MPL.
	from matplotlib import __version__ as mpl_ver
	from matplotlib import _contour
	except ImportError:
	MISSING_DEPENDENCIES = True