Support keyword & optional args

try.py

@@ -3,7 +3,7 @@ import zlib_into
 
 a = b'abcde' * 5000
 b = bytearray(5000)
-res = zlib_into.compress_into(a, b, 1, 15)
+res = zlib_into.compress_into(a, b, level=9)
 
 print("res", res)
 print(b[:res])

zlib_into.c

@@ -59,14 +59,16 @@ zlib_error(z_stream zst, int err, const char *msg)
 }
 
 static PyObject *
-compress_into(PyObject *module, PyObject *args) {
+compress_into(PyObject *module, PyObject *args, PyObject *kwargs) {
+    static char *keywords[] = {"data", "output", "level", "wbits", NULL};
     PyObject *return_value = NULL;
-    Py_buffer input, output;
     Py_ssize_t bytes_written;
-    int level, wbits;
+    Py_buffer input, output;
+    int level=Z_DEFAULT_COMPRESSION, wbits=MAX_WBITS;
     z_stream zst;
 
-    if (!PyArg_ParseTuple(args, "y*w*ii", &input, &output, &level, &wbits)) {
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*w*|ii", keywords,
+                                     &input, &output, &level, &wbits)) {
         return NULL;
     }
 
@@ -131,7 +133,7 @@ compress_into(PyObject *module, PyObject *args) {
 }
 
 static PyMethodDef ZlibIntoMethods[] = {
-    {"compress_into", compress_into, METH_VARARGS, "zlib compress data into a buffer"},
+    {"compress_into", (PyCFunction)compress_into, METH_VARARGS | METH_KEYWORDS, "zlib compress data into a buffer"},
     {NULL, NULL, 0, NULL}
 };