<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_requests_session():
 """Load requests lazily."""

    global requests_session
    if requests_session is not None:
        return requests_session
    import requests

    requests_session = requests.Session()
    adapter = requests.adapters.HTTPAdapter(
        max_retries=environments.PIPENV_MAX_RETRIES
    )
    requests_session.mount("https://pypi.org/pypi", adapter)
    return requests_session