refer to self as “this class” for staticmethods; python

Question

I am trying to construct an ETL machine for a test.

class TestETLMachine(object):

    API_URL = 'https://9g9xhayrh5.execute-api.us-west-2.amazonaws.com/test/data'

    @staticmethod
    def get_email_data(cls):
        headers = {'accept': 'application/json'}
        r = requests.get(cls.API_URL, headers=headers)
        email_objects_as_list_of_dicts = json.loads(r.content)['data']
        return email_objects_as_list_of_dicts

    @staticmethod
    def get_distinct_emails(cls):
        email_data = cls.get_email_data()
        print email_data

for get_distinct_emails I want to call TestETLMachine.get_email_data() and have it know I'm referring to this class. This object is a static machine, meaning it does the same thing always, and making instances of it is pointless and seems bad form. When I try to call get_email_data now that I pass cls I can't anymore:

In [9]: TestETLMachine.get_email_data()
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-9-cf48fc1a9c1d> in <module>()
----> 1 TestETLMachine.get_email_data()

TypeError: get_email_data() takes exactly 1 argument (0 given)

How do I call these class methods and use the other class methods in my next class methods? Salamat

Answer 1

You are looking for classmethod , not staticmethod . If you decorate a method with @classmethod , it will implicitly receive the class as first parameter.

See also the related question Meaning of @classmethod and @staticmethod for beginner?