code: func ParseSigner(pemValue string) (crypto.Signer, error) {
  	// The _ result below is not an error but the remaining PEM bytes.
  	block, _ := pem.Decode([]byte(pemValue))
  	if block == nil {
  		return nil, fmt.Errorf("no PEM-encoded data found")
  	}
  
  	switch block.Type {
  	case "EC PRIVATE KEY":
  		return x509.ParseECPrivateKey(block.Bytes)
  	default:
  		return nil, fmt.Errorf("unknown PEM block type for signing key: %s", block.Type)
  	}
  }
docs: // ParseSigner parses a crypto.Signer from a PEM-encoded key. The private key
  // is expected to be the first block in the PEM value.