code: func ParseDERSignature(sigStr []byte, curve elliptic.Curve) (*Signature, error) {
  	return parseSig(sigStr, curve, true)
  }
docs: // ParseDERSignature parses a signature in DER format for the curve type
  // `curve` into a Signature type.  If parsing according to the less strict
  // BER format is needed, use ParseSignature.