Use an enum for infer_dtype return values? #29868
Description
While working in #29799, it was quite hard to add a new return value from lib.infer_dtype. There are many places where we do something like
inferred_dtype = lib.infer_dtype(values)
if inferred_dtype == "string":
...
if inferred_dtype in {"datetime", "integer"}
...It was hard to grep for these. Could we instead define an enum
class InferredType(enum.Enum):
STRING: "string"
INTEGER: "intger"
MIXED_INTEGER: "mixed-integer"
...
And then return InferredType.INTEGER, and update all our checks for
if inferred_dtype == InferredType.INTEGERI think this should be entirely backwards compatible, since we're still just returning the string.