Do not use mutable defaults for arguments

https://google.github.io/styleguide/pyguide.html#2124-decision > Do not use mutable objects as default values in the function or method definition. An example: https://github.com/gee-community/geemap/blob/a0d51da6d2eeeb4168e79606969b548ed43f2911/geemap/plot.py#L318