@classmethod
def from_base64(cls, s, subformat='json', encoding='utf-8', **kwargs):
    """
        Load and decode Base64 data from url, filepath or data-string.
        Data is decoded according to subformat and encoding.
        Decoder specific options can be passed using kwargs.
        Return a new dict instance. A ValueError is raised in case of failure.
        """
    kwargs['subformat'] = subformat
    kwargs['encoding'] = encoding
    return cls(s, format='base64', **kwargs)
