reads the encoding type from the event-mapping.json
        and determines whether a value needs encoding

        Parameters
        ----------
        tags: dict
            the values of a particular event that can be substituted
            within the event json
        encoding: string
            string that helps navigate to the encoding field of the json
        values_to_sub: dict
            key/value pairs that will be substituted into the json
        Returns
        -------
        values_to_sub: dict
            the encoded (if need be) values to substitute into the json.

def encode(self, tags, encoding, values_to_sub):
        """
        reads the encoding type from the event-mapping.json
        and determines whether a value needs encoding

        Parameters
        ----------
        tags: dict
            the values of a particular event that can be substituted
            within the event json
        encoding: string
            string that helps navigate to the encoding field of the json
        values_to_sub: dict
            key/value pairs that will be substituted into the json
        Returns
        -------
        values_to_sub: dict
            the encoded (if need be) values to substitute into the json.
        """

        for tag in tags:
            if tags[tag].get(encoding) != "None":
                if tags[tag].get(encoding) == "url":
                    values_to_sub[tag] = self.url_encode(values_to_sub[tag])
                if tags[tag].get(encoding) == "base64":
                    values_to_sub[tag] = self.base64_utf_encode(values_to_sub[tag])
        return values_to_sub