def electrum_prv(self, s):
        """
        Parse an electrum private key from a text string in seed form ("E:xxx" where xxx
        is a 64-character hex string).
        Return a :class:`ElectrumWallet <pycoin.key.electrum.ElectrumWallet>` or None.
        """
        blob = self._electrum_to_blob(s)
        if blob and len(blob) == 32:
            mpk = from_bytes_32(blob)
            return self._network.keys.electrum_private(master_private_key=mpk)