code: public void addSignerRole(String role, int order) throws HelloSignException {
          try {
              signerRoles.add((order - 1), role);
          } catch (Exception ex) {
              throw new HelloSignException(ex);
          }
      }
docs: Adds the signer role with the given order to the list of signers for this
  request. NOTE: The order refers to the 1-base index, not 0-base. This is
  to reflect the indexing used by the HelloSign API. This means that adding
  an item at order 1 will place it in the 0th index of the list (it will be
  the first item).
  
  @param role String
  @param order int
  @throws HelloSignException thrown if there is a problem adding the signer
  role.