[Haskell-beginners] Python's collections.defaultdict(list) in Haskell?

I'm spending a little time here and there to learn some Haskell. I'm coming from a chiefly Python/C/bash background. I want to build a Data.Map where the keys are strings, and the values are lists of strings. In Python, collections.defaultdict(list) makes this pretty straightforward. It gives a hash table ("dict") that has values that default to an empty list, since list() produces an empty list. More info here: https://docs.python.org/3/library/collections.html#collections.defaultdict Is there an equivalent in Haskell? Thanks! -- Dan Stromberg