code: def has(self, relation, operator=">=", count=1, boolean="and", extra=None):
          
          if relation.find(".") >= 0:
              return self._has_nested(relation, operator, count, boolean, extra)
  
          relation = self._get_has_relation_query(relation)
  
          query = relation.get_relation_count_query(
              relation.get_related().new_query(), self
          )
  
          # TODO: extra query
          if extra:
              if callable(extra):
                  extra(query)
  
          return self._add_has_where(
              query.apply_scopes(), relation, operator, count, boolean
          )
docs: Add a relationship count condition to the query.
  
          :param relation: The relation to count
          :type relation: str
  
          :param operator: The operator
          :type operator: str
  
          :param count: The count
          :type count: int
  
          :param boolean: The boolean value
          :type boolean: str
  
          :param extra: The extra query
          :type extra: Builder or callable
  
          :type: Builder