def get_all_manifests(image_assembly_config_json):
    """Returns the list of all the package manifests mentioned in the specified product configuration.

  Args:
    image_assembly_config_json: Dictionary, holding manifest per categories.
  Returns:
    list of path to the manifest files as string.
  Raises:
    KeyError: if one of the manifest group is missing.
  """
    try:
        return image_assembly_config_json.get(
            "base", []) + image_assembly_config_json.get(
                "cache", []) + image_assembly_config_json.get("system", [])
    except KeyError as e:
        raise KeyError(
            f"Product config is missing in the product configuration: {e}")