title: Payment method token is invalid in Braintree
body: <p>I want to test it on the side of the functionality of the subscription payment gateway Braintree - for my application using Django (python).</p>
  
  <p>Your code I have only one py file. (without front-end). When I want to create a subscription I get an error:</p>
  
  <pre><code>&lt;ErrorResult 'Payment method token is invalid.' at 7f101d301390&gt;
  </code></pre>
  
  <p>How can I get token payment method?</p>
  
  <p>Here is all my code:</p>
  
  <pre><code>import braintree
  
  braintree.Configuration.configure(braintree.Environment.Sandbox,
                                    merchant_id="myMechrantId",
                                    public_key="myPublicKey",
                                    private_key="myPrivateKey")
  
  client_token = braintree.ClientToken.generate()
  
  client = braintree.Customer.create({
      "first_name": 'Mike',
      "last_name": "Smith",
      "company": "Braintree",
      "email": "jen@example.com",
      "phone": "312.555.1234",
      "fax": "614.555.5678",
      "website": "www.example.com"
  })
  
  result = braintree.Subscription.create({
      "payment_method_token": "the_token",
      "plan_id": "Here is my plan ID"
  })
  </code></pre>