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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 btc_tx_der_encode_sequence(*encoded_pieces):
 """ Return a DER-encoded sequence Based on code from python-ecdsa (https://github.com/warner/python-ecdsa) by Brian Warner. Subject to the MIT license. """

    # borrowed from python-ecdsa
    total_len = sum([len(p) for p in encoded_pieces])
    return b('\x30') + btc_tx_der_encode_length(total_len) + b('').join(encoded_pieces)