code: def _build_image(self, base_image, docker_tag, layers):
          
          dockerfile_content = self._generate_dockerfile(base_image, layers)
  
          # Create dockerfile in the same directory of the layer cache
          dockerfile_name = "dockerfile_" + str(uuid.uuid4())
          full_dockerfile_path = Path(self.layer_downloader.layer_cache, dockerfile_name)
  
          try:
              with open(str(full_dockerfile_path), "w") as dockerfile:
                  dockerfile.write(dockerfile_content)
  
              tar_paths = {str(full_dockerfile_path): "Dockerfile"}
              for layer in layers:
                  tar_paths[layer.codeuri] = '/' + layer.name
  
              with create_tarball(tar_paths) as tarballfile:
                  try:
                      self.docker_client.images.build(fileobj=tarballfile,
                                                      custom_context=True,
                                                      rm=True,
                                                      tag=docker_tag,
                                                      pull=not self.skip_pull_image)
                  except (docker.errors.BuildError, docker.errors.APIError):
                      LOG.exception("Failed to build Docker Image")
                      raise ImageBuildException("Building Image failed.")
          finally:
              if full_dockerfile_path.exists():
                  full_dockerfile_path.unlink()
docs: Builds the image
  
          Parameters
          ----------
          base_image str
              Base Image to use for the new image
          docker_tag
              Docker tag (REPOSITORY:TAG) to use when building the image
          layers list(samcli.commands.local.lib.provider.Layer)
              List of Layers to be use to mount in the image
  
          Returns
          -------
          None
  
          Raises
          ------
          samcli.commands.local.cli_common.user_exceptions.ImageBuildException
              When docker fails to build the image