code: def build(self):
          
          if os.path.exists(self.build_path) and not os.path.isdir(self.build_path):
              self._logger.error('Output path must be a folder if it already exists')
              return
          Compiler._mkdir(self.build_path)
          self._execute_backend_on_spec()
docs: Creates outputs. Outputs are files made by a backend.