def previous_sibling(self):
        """The previous sibling statement.

        :returns: The previous sibling statement node.
        :rtype: NodeNG or None
        """
        stmts = self.parent.child_sequence(self)
        index = stmts.index(self)
        if index >= 1:
            return stmts[index - 1]
        return None
The previous sibling statement.

        :returns: The previous sibling statement node.
        :rtype: NodeNG or None