import hashlib


def md5_of_string(str_to_hash: str) -> str:
    """
    convert string to bytes, then get md5 hash

    Args:
        str_to_hash: string to be hashed
    Returns:
        hash as string
    Raises:
        None

    >>> md5_of_string('a_string')
    """
    return hashlib.md5(str_to_hash.encode("utf-8")).hexdigest()