def get_content_type(self):
raise NotImplementedError<EOL>
Contains the Content-Type header returned by a GET without accept
        headers.

        This getcontenttype property MUST be defined on any DAV compliant
        resource that returns the Content-Type header in response to a GET.
        See http://www.webdav.org/specs/rfc4918.html#PROPERTY_getcontenttype