Moved everything from previous branch, including adding -u argument, function for load_user_metadata, and basic tests.
Edited help messgae, included docstring and more tests. Tested good cases (no inputs, put quotes around whitespace, no whitespaces before and after =, specify repeated keys, pairs with more than one = sign) and bad cases (do not put quotes around whitespace). I'm not sure if the inputs for test cases are intuitive enough. For example, if I specify -u weather=rainy day=tuesday or -u "weather=rainy" "day=tuesday", then they are both interpreted as ["weather=rainy", "day=tuesday"] when I print args.user_metadata. So this is what I put for inputs.
-u weather=rainy day=tuesday
or-u "weather=rainy" "day=tuesday"
, then they are both interpreted as["weather=rainy", "day=tuesday"]
when I print args.user_metadata. So this is what I put for inputs.