Function pkcs7_pad 

pub fn pkcs7_pad<'py>(
    py: Python<'py>,
    data: &[u8],
    block_size: usize,
) -> PyResult<Bound<'py, PyBytes>>

Apply PKCS#7 padding to data.

block_size is the cipher block size in bytes (16 for AES, 8 for 3DES). Raises :exc:ValueError if block_size is 0 or greater than 255.

import synta

padded = synta.pkcs7_pad(b"hello", 8)   # → b"hello\x03\x03\x03"