Removes given pattern from the Model.

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

def remove_pattern(self, pattern):
        """
        Removes given pattern from the Model.

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

        for index, node in enumerate(self.root_node.children):
            if node.name != pattern:
                continue

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

            self.beginRemoveRows(self.get_node_index(self.root_node), index, index)
            pattern_node = self.root_node.child(index)
            self.root_node.remove_child(index)
            self.endRemoveRows()
            self.pattern_removed.emit(pattern_node)
            return True