docs: def p_expression_invar(self, p):
          ''' expression    :   expression IN VAR 
          '''
          _LOGGER.debug("expresion -> expresion IN VAR")
      
          if p[3] not in self._VAR_VALUES:
              if self._autodefine_vars:
                  self._VAR_VALUES[p[3]] = TypedList([])
              else:
                  raise TypeError("list expected for IN operator")
              
          l = self._VAR_VALUES[p[3]]
          if l.type != TypedList.LIST: raise TypeError("list expected for IN operator")
          p[3] = l
          
          self.p_expression_inlist(p)