<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def pip_install(*args):
    '''
    Run pip install ...

    Explicitly ignores user's config.
    '''
    pip_cmd = os.path.join(os.path.dirname(sys.executable), 'pip')
    with set_env('PIP_CONFIG_FILE', os.devnull):
        cmd = [pip_cmd, 'install'] + list(args)
        print_command(cmd)
        subprocess.call(cmd, stdout=sys.stdout, stderr=sys.stderr)