def validate_scheme(scheme):
    """ Validate that the scheme is identical to scheme(s) we support. (HTTPS.)

    >>> assert validate_scheme('https')
    >>> validate_scheme('http') # doctest: +ELLIPSIS
    Traceback (most recent call last):
      ...
    ValueError: ... HTTPS ...
    >>> validate_scheme('httpss') # doctest: +ELLIPSIS
    Traceback (most recent call last):
      ...
    ValueError: ... HTTPS ...
    >>> validate_scheme(None) # doctest: +ELLIPSIS
    Traceback (most recent call last):
      ...
    ValueError: ... HTTPS ...
    """
    if (scheme or '').lower() == u'https':
        return True
    else:
        raise ValueError("Only HTTPS APIs are supported by Veracode.")