[Answered ]-How to use parameters in class view and url?

def get_context_data(self, request, **kwargs): 

Try to change your function declaration to include request parameter.

I’m not sure but this is probably caused by missing self parameter in custom method (which is not static).

Change this:

def case_groups(date_1, date_2, process_group):

To this:

@staticmethod
def case_groups(date_1, date_2, process_group):