Loads a template.

        :param str name: The template name
        :param str parent_path: The optional path for a parent document
        :rtype: tornado.template.Template

def load(self, name, parent_path=None):
        """Loads a template.

        :param str name: The template name
        :param str parent_path: The optional path for a parent document
        :rtype: tornado.template.Template

        """
        if name not in self.templates:
            self.templates[name] = self._create_template(name)
        return self.templates[name]