<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_to_snake(s: str) -> str: """Convert string from camel case to snake case."""


    return CAMEL_CASE_RE.sub(r'_\1', s).strip().lower()