A fake field data container used to calculate dependencies.
Create a new dictionary with keys from iterable and values set to value.
Return the value for key if key is in the dictionary, else default.
If key is not found, d is returned if given, otherwise KeyError is raised
Remove and return a (key, value) pair as a 2-tuple.
Insert key with a value of default if key is not in the dictionary.
If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]
Factory for default value called by __missing__().