docs: def get_condition(self):
          """
          Determines the condition to be used in the condition part of the join sql.
  
          :return: The condition for the join clause
          :rtype: str or None
          """
          if self.condition:
              return self.condition
  
          if type(self.right_table) is ModelTable and type(self.right_table) is ModelTable:
              # loop through fields to find the field for this model
  
              # check if this join type is for a related field
              for field in self.get_all_related_objects(self.right_table):
                  related_model = field.model
                  if hasattr(field, 'related_model'):
                      related_model = field.related_model
                  if related_model == self.left_table.model:
                      table_join_field = field.field.column
                      # self.table_join_name = field.get_accessor_name()
                      condition = '{0}.{1} = {2}.{3}'.format(
                          self.right_table.get_identifier(),
                          self.right_table.model._meta.pk.name,
                          self.left_table.get_identifier(),
                          table_join_field,
                      )
                      return condition
  
              # check if this join type is for a foreign key
              for field in self.right_table.model._meta.fields:
                  if (
                      field.get_internal_type() == 'OneToOneField' or
                      field.get_internal_type() == 'ForeignKey'
                  ):
                      if field.remote_field.model == self.left_table.model:
                          table_join_field = field.column
                          # self.table_join_name = field.name
                          condition = '{0}.{1} = {2}.{3}'.format(
                              self.right_table.get_identifier(),
                              table_join_field,
                              self.left_table.get_identifier(),
                              self.left_table.model._meta.pk.name
                          )
                          return condition
          return None