code: def btc_tx_der_encode_sequence(*encoded_pieces):
      
      # 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)
docs: 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.