import re


def camel_to_snake_case(camel_case_name: str) -> str:
    """
    Converts a name with Capital first letters to lower case with '_' as separators.
    For example, CamelToSnakeCase -> camel_to_snake_case.
    """
    return (camel_case_name[0] + re.sub(r'([A-Z])', r'_\1', camel_case_name[1:])).lower()