Inserts given pattern into the Model.

        :param pattern: Pattern.
        :type pattern: unicode
        :param index: Insertion index.
        :type index: int
        :return: Method success.
        :rtype: bool

def insert_pattern(self, pattern, index):
        """
        Inserts given pattern into the Model.

        :param pattern: Pattern.
        :type pattern: unicode
        :param index: Insertion index.
        :type index: int
        :return: Method success.
        :rtype: bool
        """

        LOGGER.debug("> Inserting '{0}' at '{1}' index.".format(pattern, index))

        self.remove_pattern(pattern)

        self.beginInsertRows(self.get_node_index(self.root_node), index, index)
        pattern_node = PatternNode(name=pattern)
        self.root_node.insert_child(pattern_node, index)
        self.endInsertRows()
        self.pattern_inserted.emit(pattern_node)
        return True