function(download_pybind11)
  if(CMAKE_VERSION VERSION_LESS 3.11)
    list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/Modules)
  endif()

  include(FetchContent)

  set(pybind11_URL  "https://github.com/pybind/pybind11/archive/refs/tags/v2.9.2.tar.gz")
  set(pybind11_HASH "SHA256=6bd528c4dbe2276635dc787b6b1f2e5316cf6b49ee3e150264e455a0d68d19c1")

  # If you don't have access to the Internet, please download it to your
  # local drive and modify the following line according to your needs.
  if(EXISTS "/star-fj/fangjun/download/github/pybind11-2.9.2.tar.gz")
    set(pybind11_URL  "file:///star-fj/fangjun/download/github/pybind11-2.9.2.tar.gz")
  elseif(EXISTS "/Users/fangjun/Downloads/pybind11-2.9.2.tar.gz")
    set(pybind11_URL  "file:///Users/fangjun/Downloads/pybind11-2.9.2.tar.gz")
  elseif(EXISTS "/tmp/pybind11-2.9.2.tar.gz")
    set(pybind11_URL  "file:///tmp/pybind11-2.9.2.tar.gz")
  endif()

  FetchContent_Declare(pybind11
    URL               ${pybind11_URL}
    URL_HASH          ${pybind11_HASH}
  )

  FetchContent_GetProperties(pybind11)
  if(NOT pybind11_POPULATED)
    message(STATUS "Downloading pybind11 from ${pybind11_URL}")
    FetchContent_Populate(pybind11)
  endif()
  message(STATUS "pybind11 is downloaded to ${pybind11_SOURCE_DIR}")
  add_subdirectory(${pybind11_SOURCE_DIR} ${pybind11_BINARY_DIR} EXCLUDE_FROM_ALL)
endfunction()

download_pybind11()