code: func fromHex(s string) *big.Int {
  	r, ok := new(big.Int).SetString(s, 16)
  	if !ok {
  		panic("invalid hex in source file: " + s)
  	}
  	return r
  }
docs: // fromHex converts the passed hex string into a big integer pointer and will
  // panic is there is an error.  This is only provided for the hard-coded
  // constants so errors in the source code can bet detected. It will only (and
  // must only) be called for initialization purposes.