code: def delete(self, custom_field, params={}, **options): 
          
          path = "/custom_fields/%s" % (custom_field)
          return self.client.delete(path, params, **options)
docs: A specific, existing custom field can be deleted by making a DELETE request on the URL for that custom field.
          
          Returns an empty data record.
  
          Parameters
          ----------
          custom_field : {Id} Globally unique identifier for the custom field.