Modify the properties of an existing document
    signature -- The signature for the desired document
    data      -- A Dictionary with the new allowed value eg. {'allow': false}

def put_document(self, signature, data):
    """ 
    Modify the properties of an existing document
    signature -- The signature for the desired document
    data      -- A Dictionary with the new allowed value eg. {'allow': false}
    """
    return self._call('PUT', self._generate_url_path('documents', signature), data)