code: public static void registerSigner(
              final String signerType,
              final Class<? extends Signer> signerClass) {
  
          if (signerType == null) {
              throw new IllegalArgumentException("signerType cannot be null");
          }
          if (signerClass == null) {
              throw new IllegalArgumentException("signerClass cannot be null");
          }
  
          SIGNERS.put(signerType, signerClass);
      }
docs: Register an implementation class for the given signer type.
  
  @param signerType  The name of the signer type to register.
  @param signerClass The class implementing the given signature protocol.