title: Get more details out of a `ConditionalCheckFailedException` in AWS DynamoDB?
body: <p>In DynamoDB it is possible to set a <code>ConditionExpression</code> on a single attribute like this:</p>
  
  <pre><code>ConditionExpression: 'attribute_exists(user_id)'
  </code></pre>
  
  <p>If this ConditionExpression is defined on an update, and the user_id does not exist, the ConditionExpression evaluates to false and returns an exception:</p>
  
  <pre><code>message: 'The conditional request failed',
  code: 'ConditionalCheckFailedException',
  requestId: 'KPFMA7S5P110FCOMLPMKP15UDBVV4KQNSO6AEMVJF66Q9ASUAAJG',
  statusCode: 400
  </code></pre>
  
  <p>Whilst there is only one condition to evaluate everything is clear, but when multiple conditions are specified, DynamoDB does not report which condition failed:</p>
  
  <pre><code>ConditionExpression: 'attribute_exists(user_id) and iq = 85'
  </code></pre>
  
  <p>then exception is the same as above, thus it's impossible to say what exactly caused the condition evaluated to false. </p>
  
  <p>Is there a way (even hacky one) to get more details out of that exception information?</p>