code: def _involvedTables(self):
          
          # SQL and arguments
          if self.comparison is not None:
              tables = self.comparison.getInvolvedTables()
              self.args = self.comparison.getArgs(self.store)
          else:
              tables = list(self.tableClass)
              self.args = []
  
          for tableClass in self.tableClass:
              if tableClass not in tables:
                  raise ValueError(
                      "Comparison omits required reference to result type %s"
                      % tableClass.typeName)
  
          return tables
docs: Return a list of tables involved in this query,
          first checking that no required tables (those in
          the query target) have been omitted from the comparison.