code: func RemoveChecksum(input Trytes) (Trytes, error) {
  	if !guards.IsTrytesOfExactLength(input, HashTrytesSize) &&
  		!guards.IsTrytesOfExactLength(input, AddressWithChecksumTrytesSize) {
  		return "", ErrInvalidAddress
  	}
  	return input[:HashTrytesSize], nil
  }
docs: // RemoveChecksum removes the checksum from the given trytes.
  // The input trytes must be of length HashTrytesSize or AddressWithChecksumTrytesSize.