def user
      response = JSON.parse(@client.get("wallet_accounts/#{send(:id)}/users").body)
      response.key?('users') ? Promisepay::User.new(@client, response['users']) : nil
    end
def user
      response = JSON.parse(@client.get("wallet_accounts/#{send(:id)}/users").body)
      response.key?('users') ? Promisepay::User.new(@client, response['users']) : nil
    end
Show the User the Wallet Account is associated with

 @return [Promisepay::User]