[Python] reserved keywords should include common types

[gs11]

Description

When a Swagger file includes fields named like common Python types (date, float etc), from_dict() will fail with:

TypeError: 'NoneType' object is not callable

Swagger-codegen version

2.3.1

Swagger declaration file content or url

https://gist.github.com/gs11/b314d66f10e1c795178b821cf46934e8

Command line used for generation

java -jar swagger-codegen-cli-2.3.1.jar generate -l python-flask -i swagger/petstore-minimal.yaml -o swagger

Steps to reproduce

In the controller, convert the Pet() object to a dict and then convert it back:

    pet = Pet()
    pet.id = 12345
    pet.name = "ACME pet"
    pet.tag = "generic"
    pet.date = "2018-04-02"
    pet.int = "test"
    pet.str = "test"
    pet.float = "test"
    pet.datetime = datetime.datetime.now()

    pet_as_dict = pet.to_dict()
    new_pet = Pet.from_dict(pet_as_dict)

Related issues/PRs

#6111

Suggest a fix/enhancement

Extend the lists with the following keywords:
float, int, str, date, datetime

[gs11]

Working on a fix, will submit PR.

[gs11]

See PR #7956

[gs11]

PR merged

[tomer]

Extend the lists with the following keywords:
float, int, str, date, datetime

Can you please add type and id as well all other built-in functions? These keywords are not prohibited as the reserved words, but it is generally good idea not to use them in code, as they are masking the built-in functions. Since there are already some keywords in the list that are not reserved (including self, which is nothing but common naming best practice to reference to the instance), I suggest expanding the list of reserved keywords to include all the built-in functions.