import re


def camel_to_snake_case(camel_cased_string):
    """Convert the format of the given string from CamelCase to snake_case.

    Args:
      camel_cased_string: the string in CamelCase format.

    Returns:
      the same string, but in snake_case format.

    """
    return re.sub(r"(?<!^)(?=[A-Z])", "_", camel_cased_string).lower()