code: public void createBankAccountToken(
              @NonNull final BankAccount bankAccount,
              @NonNull @Size(min = 1) final String publishableKey,
              @Nullable final Executor executor,
              @NonNull final TokenCallback callback) {
          if (bankAccount == null) {
              throw new RuntimeException(
                      "Required parameter: 'bankAccount' is requred to create a token");
          }
  
          createTokenFromParams(
                  mStripeNetworkUtils.hashMapFromBankAccount(bankAccount),
                  publishableKey,
                  Token.TYPE_BANK_ACCOUNT,
                  executor,
                  callback);
      }
docs: Call to create a {@link Token} for a {@link BankAccount} with the publishable key and
  {@link Executor} specified.
  
  @param bankAccount the {@link BankAccount} for which to create a {@link Token}
  @param publishableKey the publishable key to use
  @param executor an {@link Executor} to run this operation on. If null, this is run on a
  default non-ui executor
  @param callback a {@link TokenCallback} to receive the result or error message