not completed but commiting anyway

The trick here is parsing the input_format and the output_format.
If temperature is `temperature[:-1]` then 'input_format = temperature[-1].lower()`

Once you have input format you can line up your ifs:

    if input_format == output_format:
        # do nothing!
    if input_format == 'c' and output_format == 'f':
        # use one of your functions
    if input_format == 'f' and output_format == 'c':
        # use the other of your functions
    else:
        # get none again

You don't have to cast your result as float() since it's already either returning as one from the other calculations or is None