Better docstring for JsonPayload

        Object to wrap up simple functionality for parsing a JSON response.

        """

        # Try to load as json

        self.json = request.get_json()

        self.json = request.get_json()  #: dict: Dictionary representation of request JSON

        # Store raw response data

        self.data = request.get_data()

        self.data = request.get_data()  #: str: String representation of request data

    def param(self, key, default=None, convert=None):

        """Check if a key exists in a JSON/dictionary payload, and returns it."""

        """

        Check if a key exists in a JSON/dictionary payload, and returns it.

        Args:

            key (str): JSON key to look for

            default: Value to return if no matching key-value pair is found.

            convert: Converter function. By passing a type, the value will be converted to that type. **Use with caution!**

        """

        # If no JSON payload exists, return early

        if not self.json:

            return None