from enum import Enum

class OptionType(Enum):
    OP1 = 'FirstOp'
    OP2 = 'SecondOp'
    OP3 = 'ThirdOp'


class SomeAPI(Consumer):
    @returns.json()
    @get("/path")
    def list_elements(self,
                   option_type: Query(type=OptionType),
                   page: Query(type=int) = 0,
                   limit: Query(type=int) = 100
                   ):
        """ Get list """
        ...

if __name__ == '__main__':
    session = requests.Session()
    client = SomeAPI('http://localhost:5000', client=session)
    resp = client.list_elements(option_type=OptionType.OP1)