* `pkgs.pypy2Packages` pointing to `pkgs.pypy27Packages`
* `pkgs.pypy3Packages` pointing to `pkgs.pypy310Packages`
* `pkgs.pypyPackages` pointing to `pkgs.pypy2Packages`


#### `buildPythonPackage` function {#buildpythonpackage-function}

The `buildPythonPackage` function has its name binding in
`pkgs/development/interpreters/python/python-packages-base.nix` and is
implemented in `pkgs/development/interpreters/python/mk-python-derivation.nix`
using setup hooks.

The following is an example:

```nix
{
  lib,
  buildPythonPackage,
  fetchPypi,

  # build-system
  setuptools,
  setuptools-scm,

  # dependencies
  attrs,
  pluggy,
  py,
  setuptools,
  six,

  # tests
  hypothesis,
}:

buildPythonPackage rec {
  pname = "pytest";
  version = "3.3.1";
  pyproject = true;

  src = fetchPypi {
    inherit pname version;
    hash = "sha256-z4Q23FnYaVNG/NOrKW3kZCXsqwDWQJbOvnn7Ueyy65M=";
  };

  postPatch = ''
    # don't test bash builtins
    rm testing/test_argcomplete.py
  '';

  build-system = [
    setuptools
    setuptools-scm
  ];

  dependencies = [
    attrs
    py
    setuptools
    six
    pluggy
  ];

  nativeCheckInputs = [
    hypothesis
  ];

  meta = {
    changelog = "https://github.com/pytest-dev/pytest/releases/tag/${version}";
    description = "Framework for writing tests";
    homepage = "https://github.com/pytest-dev/pytest";
    license = lib.licenses.mit;
    maintainers = with lib.maintainers; [
      domenkozar
      lovek323
      madjar
      lsix
    ];
  };
}
```

The `buildPythonPackage` mainly does four things:

* In the [`buildPhase`](#build-phase), it calls `${python.pythonOnBuildForHost.interpreter} -m build --wheel` to
  build a wheel binary zipfile.
* In the [`installPhase`](#ssec-install-phase), it installs the wheel file using `${python.pythonOnBuildForHost.interpreter} -m installer *.whl`.
* In the [`postFixup`](#var-stdenv-postFixup) phase, the `wrapPythonPrograms` bash function is called to
  wrap all programs in the `$out/bin/*` directory to include `$PATH`
  environment variable and add dependent libraries to script's `sys.path`.
* In the [`installCheck`](#ssec-installCheck-phase) phase, `${python.interpreter} -m pytest` is run.

By default tests are run because [`doCheck = true`](#var-stdenv-doCheck). Test dependencies, like
e.g. the test runner, should be added to [`nativeCheckInputs`](#var-stdenv-nativeCheckInputs).

By default `meta.platforms` is set to the same value
as the interpreter unless overridden otherwise.

##### `buildPythonPackage` parameters {#buildpythonpackage-parameters}

All parameters from [`stdenv.mkDerivation`](#sec-using-stdenv) function are still supported. The
following are specific to `buildPythonPackage`:

* `catchConflicts ? true`: If `true`, abort package build if a package name
  appears more than once in dependency tree. Default is `true`.
* `disabled ? false`: If `true`, package is not built for the particular Python
  interpreter version.
* `dontWrapPythonPrograms ? false`: Skip wrapping of Python programs.
* `permitUserSite ? false`: Skip setting the `PYTHONNOUSERSITE` environment
  variable in wrapped programs.
* `pyproject`: Whether the pyproject format should be used. As all other formats
  are deprecated, you are recommended to set this to `true`. When you do so,
  `pypaBuildHook` will be used, and you can add the required build dependencies
  from `build-system.requires` to `build-system`. Note that the pyproject
  format falls back to using `setuptools`, so you can use `pyproject = true`
  even if the package only has a `setup.py`. When set to `false`, you can
  use the existing [hooks](#setup-hooks) or provide your own logic to build the
  package. This can be useful for packages that don't support the pyproject
  format. When unset, the legacy `setuptools` hooks are used for backwards
  compatibility.
* `makeWrapperArgs ? []`: A list of strings. Arguments to be passed to
  [`makeWrapper`](#fun-makeWrapper), which wraps generated binaries. By default, the arguments to