code: public void setSigner(String role, String email, String name) throws HelloSignException {
          signers.put(role, new Signer(email, name));
      }
docs: Adds the signer to the list of signers for this request.
  
  @param role String
  @param email String
  @param name String
  @throws HelloSignException thrown if there is a problem setting the
  signer.