title: Return all class variable values from a Python Class
body: <p>I have a Python class that contains all the AWS regions. I wrote a class method that would return me the list of all the regions. Is there a better way of returning all the class variable values so I don't have to hard-code all the values in the return statement like I am doing in the example below?</p>
  
  <pre><code>class AwsRegion():
      '''
      Class to define AWS Regions
      '''
      OHIO = 'us-east-2'
      NORTH_VIRGINIA = 'us-east-1'
      NORTH_CALIFORNIA = 'us-west-1'
      OREGON = 'us-west-2'
      MUMBAI = 'ap-south-1'
      SEOUL = 'ap-northeast-2'
      SINGAPORE = 'ap-southeast-1'
      SYDNEY = 'ap-southeast-2'
      TOKYO = 'ap-northeast-1'
      FRANKFURT = 'eu-central-1'
      IRELAND = 'eu-west-1'
      LONDON = 'eu-west-2'
      SAO_PAULO = 'sa-east-1'
  
      @classmethod
      def all(cls, ):
          return [AwsRegion.OHIO, AwsRegion.NORTH_VIRGINIA, AwsRegion.NORTH_CALIFORNIA, AwsRegion.OREGON, \
              AwsRegion.MUMBAI, AwsRegion.SEOUL, AwsRegion.SINGAPORE, AwsRegion.SYDNEY, AwsRegion.TOKYO, \
              AwsRegion.FRANKFURT, AwsRegion.IRELAND, AwsRegion.LONDON, AwsRegion.SAO_PAULO]
  </code></pre>