code: def get_yaml_files_at_env_root(self):
          
          yaml_files = glob.glob(
              os.path.join(self.env_root, '*.yaml')
          )
          yml_files = glob.glob(
              os.path.join(self.env_root, '*.yml')
          )
          return yaml_files + yml_files
docs: Return list of yaml files in env_root.