How to use the pip._internal.utils.typing.MYPY_CHECK_RUNNING function in pip

# The following comment should be removed at some point in the future.
# mypy: strict-optional=False

from __future__ import absolute_import

import os
import re
import warnings

from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import Optional, Tuple


def glibc_version_string():
    # type: () -> Optional[str]
    "Returns glibc version string, or None if not using glibc."
    return glibc_version_string_confstr() or glibc_version_string_ctypes()


def glibc_version_string_confstr():
    # type: () -> Optional[str]
    "Primary implementation of glibc_version_string using os.confstr."
    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
    # to be broken or missing. This strategy is used in the standard library
    # platform module:
    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183

"""

# The following comment should be removed at some point in the future.
# mypy: disallow-untyped-defs=False

from __future__ import absolute_import

import os
import sys

from pip._vendor.six import PY2, text_type

from pip._internal.utils.compat import WINDOWS, expanduser
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import List


def user_cache_dir(appname):
    # type: (str) -> str
    r"""
    Return full path to the user-specific cache dir for this application.

        "appname" is the name of application.

    Typical user cache directories are:
        macOS:      ~/Library/Caches/
        Unix:       ~/.cache/ (XDG default)
        Windows:    C:\Users\\AppData\Local\\Cache

    On Windows the only suggestion in the MSDN docs is that local settings go

from pip._internal.exceptions import CommandError, InstallationError
from pip._internal.locations import (
    running_under_virtualenv, site_packages, user_site, virtualenv_no_global,
    write_delete_marker_file,
)
from pip._internal.utils.compat import (
    WINDOWS, console_to_str, expanduser, stdlib_pkgs,
)
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if PY2:
    from io import BytesIO as StringIO
else:
    from io import StringIO

if MYPY_CHECK_RUNNING:
    from typing import (  # noqa: F401
        Optional, Tuple, Iterable, List, Match, Union, Any, Mapping, Text,
        AnyStr, Container
    )
    from pip._vendor.pkg_resources import Distribution  # noqa: F401
    from pip._internal.models.link import Link  # noqa: F401
    from pip._internal.utils.ui import SpinnerInterface  # noqa: F401


__all__ = ['rmtree', 'display_path', 'backup_dir',
           'ask', 'splitext',
           'format_size', 'is_installable_dir',
           'is_svn_page', 'file_contents',
           'split_leading_dir', 'has_leading_dir',
           'normalize_path',
           'renames', 'get_prog',

import shutil
import stat
import tarfile
import zipfile

from pip._internal.exceptions import InstallationError
from pip._internal.utils.filetypes import (
    BZ2_EXTENSIONS,
    TAR_EXTENSIONS,
    XZ_EXTENSIONS,
    ZIP_EXTENSIONS,
)
from pip._internal.utils.misc import ensure_dir
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import Iterable, List, Optional, Text, Union


logger = logging.getLogger(__name__)


SUPPORTED_EXTENSIONS = ZIP_EXTENSIONS + TAR_EXTENSIONS

try:
    import bz2  # noqa
    SUPPORTED_EXTENSIONS += BZ2_EXTENSIONS
except ImportError:
    logger.debug('bz2 module is not available')

try:
    # Only for Python 3.3+

"""

import os
import sys

from pip._internal.cli import cmdoptions
from pip._internal.cli.parser import (
    ConfigOptionParser,
    UpdatingDefaultsHelpFormatter,
)
from pip._internal.commands import commands_dict, get_similar_commands
from pip._internal.exceptions import CommandError
from pip._internal.utils.misc import get_pip_version, get_prog
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import Tuple, List


__all__ = ["create_main_parser", "parse_command"]


def create_main_parser():
    # type: () -> ConfigOptionParser
    """Creates and returns the main parser for pip's CLI
    """

    parser_kw = {
        'usage': '\n%prog  [options]',
        'add_help_option': False,
        'formatter': UpdatingDefaultsHelpFormatter(),
        'name': 'global',

expanduser,
    stdlib_pkgs,
    str_to_display,
)
from pip._internal.utils.typing import MYPY_CHECK_RUNNING, cast
from pip._internal.utils.virtualenv import (
    running_under_virtualenv,
    virtualenv_no_global,
)

if PY2:
    from io import BytesIO as StringIO
else:
    from io import StringIO

if MYPY_CHECK_RUNNING:
    from typing import (
        Any, AnyStr, Container, Iterable, Iterator, List, Optional, Text,
        Tuple, Union,
    )
    from pip._vendor.pkg_resources import Distribution

    VersionInfo = Tuple[int, int, int]


__all__ = ['rmtree', 'display_path', 'backup_dir',
           'ask', 'splitext',
           'format_size', 'is_installable_dir',
           'normalize_path',
           'renames', 'get_prog',
           'captured_stdout', 'ensure_dir',
           'get_installed_version', 'remove_auth_from_url']

from pip._internal.exceptions import (
    BestVersionAlreadyInstalled, DistributionNotFound, HashError, HashErrors,
    UnsupportedPythonVersion,
)
from pip._internal.req.constructors import install_req_from_req_string
from pip._internal.utils.logging import indent_log
from pip._internal.utils.misc import (
    dist_in_usersite, ensure_dir, normalize_version_info,
)
from pip._internal.utils.packaging import (
    check_requires_python, get_requires_python,
)
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import DefaultDict, List, Optional, Set, Tuple
    from pip._vendor import pkg_resources

    from pip._internal.cache import WheelCache
    from pip._internal.distributions import AbstractDistribution
    from pip._internal.download import PipSession
    from pip._internal.index import PackageFinder
    from pip._internal.operations.prepare import RequirementPreparer
    from pip._internal.req.req_install import InstallRequirement
    from pip._internal.req.req_set import RequirementSet

logger = logging.getLogger(__name__)


def _check_dist_requires_python(
    dist,  # type: pkg_resources.Distribution

)
from pip._internal.index import PackageFinder
from pip._internal.locations import running_under_virtualenv
from pip._internal.req.req_file import parse_requirements
from pip._internal.req.req_install import InstallRequirement
from pip._internal.status_codes import (
    ERROR, PREVIOUS_BUILD_DIR_ERROR, SUCCESS, UNKNOWN_ERROR,
    VIRTUALENV_NOT_FOUND,
)
from pip._internal.utils import deprecation
from pip._internal.utils.logging import IndentingFormatter
from pip._internal.utils.misc import get_prog, normalize_path
from pip._internal.utils.outdated import pip_version_check
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import Optional

__all__ = ['Command']

logger = logging.getLogger(__name__)


class Command(object):
    name = None  # type: Optional[str]
    usage = None  # type: Optional[str]
    hidden = False  # type: bool
    ignore_require_venv = False  # type: bool
    log_streams = ("ext://sys.stdout", "ext://sys.stderr")

    def __init__(self, isolated=False):
        parser_kw = {

import sys

from pip._internal.cli.main import main
from pip._internal.utils.typing import MYPY_CHECK_RUNNING

if MYPY_CHECK_RUNNING:
    from typing import Optional, List


def _wrapper(args=None):
    # type: (Optional[List[str]]) -> int
    """Central wrapper for all old entrypoints.

    Historically pip has had several entrypoints defined. Because of issues
    arising from PATH, sys.path, multiple Pythons, their interactions, and most
    of them having a pip installed, users suffer every time an entrypoint gets
    moved.

    To alleviate this pain, and provide a mechanism for warning users and
    directing them to an appropriate place for help, we now define all of
    our old entrypoints as wrappers for the current one.
    """

from pip._internal.index.collector import parse_links
from pip._internal.models.candidate import InstallationCandidate
from pip._internal.models.format_control import FormatControl
from pip._internal.models.link import Link
from pip._internal.models.selection_prefs import SelectionPreferences
from pip._internal.models.target_python import TargetPython
from pip._internal.models.wheel import Wheel
from pip._internal.utils.filetypes import WHEEL_EXTENSION
from pip._internal.utils.logging import indent_log
from pip._internal.utils.misc import build_netloc
from pip._internal.utils.packaging import check_requires_python
from pip._internal.utils.typing import MYPY_CHECK_RUNNING
from pip._internal.utils.unpacking import SUPPORTED_EXTENSIONS
from pip._internal.utils.urls import url_to_path

if MYPY_CHECK_RUNNING:
    from typing import (
        FrozenSet, Iterable, List, Optional, Set, Text, Tuple, Union,
    )
    from pip._vendor.packaging.version import _BaseVersion
    from pip._internal.index.collector import LinkCollector
    from pip._internal.models.search_scope import SearchScope
    from pip._internal.req import InstallRequirement
    from pip._internal.pep425tags import Pep425Tag
    from pip._internal.utils.hashes import Hashes

    BuildTag = Union[Tuple[()], Tuple[int, str]]
    CandidateSortingKey = (
        Tuple[int, int, int, _BaseVersion, BuildTag, Optional[int]]
    )