def convert_string_to_float(s):
    """
    Attempt to convert a string to a float.

    Parameters
    ---------
    s : str
        The string to convert

    Returns
    -------
    : float / str
      If successful, the converted value, else the argument is passed back
      out.
    """
    
    try:
        return float(s)
    except TypeError:
        return s