@staticmethod
def query_str(query_dict):
    """ Takes a RequestQuery object and returns a proper Aeris API url query

            Params:
                - query_dict: A dictionary containing a single RequestQuery and its value

            Returns:
                - str: a correctly formatted query attribute ready to be inserted into an API request url
        """
    out_query = ''
    if query_dict is not None:
        for q, value in query_dict.items():
            out_query += '&' + q.value + '=' + value
    else:
        out_query = None
    return out_query
