'Returns the descriptions of existing applications.
:type application_names: list
:param application_names: If specified, AWS Elastic Beanstalk restricts
the returned descriptions to only include those with the specified
names.'

def describe_applications(self, application_names=None):

    params = {}
    if application_names:
        self.build_list_params(params, application_names, 'ApplicationNames.member')
    return self._get_response('DescribeApplications', params)
