<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def camel_case_to_snake_case(name):
 """ HelloWorld -> hello_world """

    s1 = _FIRST_CAP_RE.sub(r'\1_\2', name)
    return _ALL_CAP_RE.sub(r'\1_\2', s1).lower()