(str_arr)
return bytes(str_arr, 'utf-8')
'hello' -> b'hello'
    :param str_arr: str
    :return: bytes
'hello' -> b'hello'
    :param str_arr: str
    :return: bytes
hello - > b hello : param str_arr : str : return : bytes
def str_to_bytes(str_arr):
    """
    'hello' -> b'hello'
    :param str_arr: str
    :return: bytes
    """
    return bytes(str_arr, 'utf-8')
def str_to_bytes ( str_arr ) : return bytes ( str_arr , 'utf-8' )