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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def download_from(self, buff, remote_path):
 """Downloads file from WebDAV and writes it in buffer. :param buff: buffer object for writing of downloaded file content. :param remote_path: path to file on WebDAV server. """

        urn = Urn(remote_path)
        if self.is_dir(urn.path()):
            raise OptionNotValid(name='remote_path', value=remote_path)

        if not self.check(urn.path()):
            raise RemoteResourceNotFound(urn.path())

        response = self.execute_request(action='download', path=urn.quote())
        buff.write(response.content)