_node_add_with_peer_leaf

        Low-level api: Apply delta child_other to child_self when child_self is
        the peer of child_other. Element child_self and child_other are leaf
        nodes. Element child_self will be modified during the process. RFC6020
        section 7.6.7 is a reference of this method.

        Parameters
        ----------

        child_self : `Element`
            A child of a config node in a config tree.

        child_other : `Element`
            A child of a config node in another config tree. child_self is
            the peer of child_other.

        Returns
        -------

        None
            There is no return of this method.

def _node_add_with_peer_leaf(self, child_self, child_other):
        '''_node_add_with_peer_leaf

        Low-level api: Apply delta child_other to child_self when child_self is
        the peer of child_other. Element child_self and child_other are leaf
        nodes. Element child_self will be modified during the process. RFC6020
        section 7.6.7 is a reference of this method.

        Parameters
        ----------

        child_self : `Element`
            A child of a config node in a config tree.

        child_other : `Element`
            A child of a config node in another config tree. child_self is
            the peer of child_other.

        Returns
        -------

        None
            There is no return of this method.
        '''

        if child_other.get(operation_tag) is None:
            child_self.text = child_other.text
        elif child_other.get(operation_tag) == 'merge':
            child_self.text = child_other.text
        elif child_other.get(operation_tag) == 'replace':
            child_self.text = child_other.text
        elif child_other.get(operation_tag) == 'create':
            raise ConfigDeltaError('data-exists: try to create node {} but ' \
                                   'it already exists' \
                                   .format(self.device.get_xpath(child_other)))
        elif child_other.get(operation_tag) == 'delete' or \
             child_other.get(operation_tag) == 'remove':
            parent_self = child_self.getparent()
            parent_self.remove(child_self)
        else:
            raise ConfigDeltaError("unknown operation: node {} contains " \
                                   "operation '{}'" \
                                   .format(self.device.get_xpath(child_other),
                                           child_other.get(operation_tag)))