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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 xrb_address_to_public_key(address):
 """ Convert an xrb address to public key in bytes '81r51e3i81r51e3i81r51e3imxssakuq') b'00000000000000000000000000000000' :param address: xrb address :type address: bytes :return: public key in bytes :rtype: bytes :raises ValueError: """


    address = bytearray(address, 'ascii')

    if not address.startswith(b'xrb_'):
        raise ValueError('address does not start with xrb_: %s' % address)

    if len(address) != 64:
        raise ValueError('address must be 64 chars long: %s' % address)

    address = bytes(address)
    key_b32xrb = b'1111' + address[4:56]
    key_bytes = b32xrb_decode(key_b32xrb)[3:]
    checksum = address[56:]

    if b32xrb_encode(address_checksum(key_bytes)) != checksum:
        raise ValueError('invalid address, invalid checksum: %s' % address)

    return key_bytes