'update the state of this Identifiers with the undeclared
and declared identifiers of the given node.'

def check_declared(self, node):

    for ident in node.undeclared_identifiers():
        if ((ident != 'context') and (ident not in self.declared.union(self.locally_declared))):
            self.undeclared.add(ident)
    for ident in node.declared_identifiers():
        self.locally_declared.add(ident)
