Summary

The documentation to ListedColormap states that the input should be a list or array

However, when specifying N, str and float are also supported (if one use the source code)

This means that, e.g., ListedColormap("#aabbcc", N=1) works, but ListedColormap("#aabbcc") does not (there will be weird errors later, like N=7 for the latter). Given that there is monochrome attribute and the documentation of N, one may expect the latter to work as well (if the earlier works). Also, ListedColormap(["#aabbcc"]) will not set the monochrome attribute correctly.

Proposed fix

I think there are three(?) possible solutions:

• Support scalars/strings when N is not provided (and ideally documents that)
• Document that if N is not None, the first argument can be a scalar or string (it is maybe easier to do ListedColormap(0.3, N=7) than ListedColormap([0.3]*7) or at least require slightly less Python knowledge)
• Deprecate scalar/string argument

Bonus: document the color and monochrome attributes