code: func (sig *Signature) IsEqual(otherSig *Signature) bool {
  	return sig.R.Cmp(otherSig.R) == 0 &&
  		sig.S.Cmp(otherSig.S) == 0
  }
docs: // IsEqual compares this Signature instance to the one passed, returning true
  // if both Signatures are equivalent. A signature is equivalent to another, if
  // they both have the same scalar value for R and S.