code: func ValidateSignatures(expectedAddress Hash, fragments Trytes, bundleHash Hash, spongeFunc ...SpongeFunction) (bool, error) {
  	bundleHashTrits, err := TrytesToTrits(bundleHash)
  	if err != nil {
  		return false, err
  	}
  
  	fragmentsTrits, err := TrytesToTrits(fragments)
  	if err != nil {
  		return false, err
  	}
  
  	digest, err := Digest(bundleHashTrits, fragmentsTrits, 0, spongeFunc...)
  	if err != nil {
  		return false, err
  	}
  
  	addressTrits, err := Address(digest, spongeFunc...)
  	if err != nil {
  		return false, err
  	}
  
  	trytes, err := TritsToTrytes(addressTrits)
  	if err != nil {
  		return false, err
  	}
  
  	return expectedAddress == trytes, nil
  }
docs: // ValidateSignatures validates the given signature fragments by checking whether the
  // digests computed from the bundle hash and fragments equal the passed address.
  // Optionally takes the SpongeFunction to use. Default is Kerl.