Get the private and public keys from a private key string.
    Make sure the both are *uncompressed*

def get_uncompressed_private_and_public_keys( privkey_str ):
    """
    Get the private and public keys from a private key string.
    Make sure the both are *uncompressed*
    """
    if not isinstance(privkey_str, (str, unicode)):
        raise ValueError("private key given is not a string")

    pk = ecdsa_private_key(str(privkey_str))
    pk_hex = pk.to_hex()

    # force uncompressed
    if len(pk_hex) > 64:
        if pk_hex[-2:] != '01':
            raise ValueError("private key does not end in '01'")

        pk_hex = pk_hex[:64]

    pubk_hex = ecdsa_private_key(pk_hex).public_key().to_hex()
    return pk_hex, pubk_hex