code: def __query__(self, q):
      if not isinstance(q, Query):
          raise TypeError("Expected a Query.", q)
      # The ordered set is needed for deterministic optimization.
      variables = OrderedSet()
      for tag in q.include:
          variables.update(self.__db__[tag])
      for tag in q.require:
          variables.intersection_update(self.__db__[tag])
      for tag in q.exclude:
          variables.difference_update(self.__db__[tag])
      remove = OrderedSet()
      add = OrderedSet()
      for obj in variables:
          if isinstance(obj, DB):
              def_sub_query = q
              if q.extra_optimizations:
                  def_sub_query = copy.copy(q)
                  def_sub_query.extra_optimizations = []
              sq = q.subquery.get(obj.name, def_sub_query)
  
              replacement = obj.query(sq)
              replacement.name = obj.name
              remove.add(obj)
              add.add(replacement)
      variables.difference_update(remove)
      variables.update(add)
      return variables
  
imports: from __future__ import absolute_import, print_function, division
  import copy
  import sys
  from theano.compat import DefaultOrderedDict
  from theano.misc.ordered_set import OrderedSet
  from six import StringIO, integer_types
  from theano.gof import opt
  from theano import config
label_desc: Use image node_id 6 for calling the DB obj's underlying member method code with example usage: obj.__query__(q) and returns: variables