@staticmethod
def print_node(node):
    """
        Debugging purpose.
        """
    r = []
    for att in ['s', 'name', 'str', 'id', 'body', 'n', 'arg', 'targets',
        'attr', 'returns', 'ctx']:
        if att in node.__dict__:
            r.append('{0}={1}'.format(att, str(node.__dict__[att])))
    return ' '.join(r)
