Get rid of the --python python/py shortcuts

src/pip/_internal/cli/main_parser.py

@@ -50,27 +50,6 @@ def create_main_parser() -> ConfigOptionParser:
 
 
 def identify_python_interpreter(python: str) -> Optional[str]:
-    if python == "python" or python == "py":
-        # Run the active Python.
-        # We have to be very careful here, because:
-        #
-        # 1. On Unix, "python" is probably correct but there is a "py" launcher.
-        # 2. On Windows, "py" is the best option if it's present.
-        # 3. On Windows without "py", "python" might work, but it might also
-        #    be the shim that launches the Windows store to allow you to install
-        #    Python.
-        #
-        # We go with getting py on Windows, and if it's not present or we're
-        # on Unix, get python. We don't worry about the launcher on Unix or
-        # the installer stub on Windows.
-        py = None
-        if WINDOWS:
-            py = shutil.which("py")
-        if py is None:
-            py = shutil.which("python")
-        if py:
-            return py
-
     # If the named file exists, use it.
     # If it's a directory, assume it's a virtual environment and
     # look for the environment's Python executable.

tests/unit/test_cmdoptions.py

@@ -35,23 +35,13 @@ def test_convert_python_version(
     assert actual == expected, f"actual: {actual!r}"
 
 
-def test_identify_python_interpreter_py(monkeypatch: pytest.MonkeyPatch) -> None:
-    def which(cmd: str) -> str:
-        assert cmd == "py" or cmd == "python"
-        return "dummy_value"
-
-    monkeypatch.setattr("shutil.which", which)
-    assert identify_python_interpreter("py") == "dummy_value"
-    assert identify_python_interpreter("python") == "dummy_value"
-
-
 def test_identify_python_interpreter_venv(tmpdir: Path) -> None:
     env_path = tmpdir / "venv"
     env = EnvBuilder(with_pip=False)
     env.create(env_path)
 
     # Passing a virtual environment returns the Python executable
-    interp = identify_python_interpreter(os.fsdecode(env_path))
+    interp = identify_python_interpreter(os.fspath(env_path))
     assert interp is not None
     assert Path(interp).exists()