Find and return the argument with key 'name'
        from JSON request data. Similar to Tornado's get_argument() method.

        :param str name: The name of the json key you want to get the value for
        :param bool default: The default value if nothing is found
        :returns: value of the argument name request

def get_json_argument(self, name, default=None):
        """Find and return the argument with key 'name'
        from JSON request data. Similar to Tornado's get_argument() method.

        :param str name: The name of the json key you want to get the value for
        :param bool default: The default value if nothing is found
        :returns: value of the argument name request
        """

        if default is None:
            default = self._ARG_DEFAULT
        if not self.request.arguments:
            self.load_json()
        if name not in self.request.arguments:
            if default is self._ARG_DEFAULT:
                msg = "Missing argument '%s'" % name
                self.logger.debug(msg)
                self.raise_error(400, msg)
            self.logger.debug("Returning default argument %s, as we couldn't "
                              "find '%s' in %s" % (default, name,
                                                   self.request.arguments))
            return default
        arg = self.request.arguments[name]
        return arg