def GetKey(self, public_key_hash):
        """
        Get the KeyPair belonging to the public key hash.

        Args:
            public_key_hash (UInt160): a public key hash to get the KeyPair for.

        Returns:
            KeyPair: If successful, the KeyPair belonging to the public key hash, otherwise None
        """
        if public_key_hash.ToBytes() in self._keys.keys():
            return self._keys[public_key_hash.ToBytes()]
        return None
Get the KeyPair belonging to the public key hash.

        Args:
            public_key_hash (UInt160): a public key hash to get the KeyPair for.

        Returns:
            KeyPair: If successful, the KeyPair belonging to the public key hash, otherwise None