Fix missing _free method on the _Image class

src/twain/__init__.py

@@ -125,15 +125,16 @@ def _twain1_alloc(size: int) -> ct.c_void_p:
     _twain1_unlock = windows.GlobalUnlock
 
     class _Image(_IImage):
-        def __init__(self, handle):
+        def __init__(self, handle, free: collections.abc.Callable[[typing.Any], None]):
             self._handle = handle
+            self._free = free
 
         def __del__(self):
             self.close()
 
         def close(self):
             """Releases memory of image"""
-            self._free(self._handle)  # type: ignore # needs fixing
+            self._free(self._handle)
             self._handle = None
 
         def save(self, filepath: str):
@@ -904,7 +905,7 @@ def acquire_natively(
         def xfer_ready_callback() -> int:
             before(self.image_info)
             handle, more = self.xfer_image_natively()
-            after(_Image(handle), more)  # type: ignore # needs fixing
+            after(_Image(handle=handle, free=self._free), more)  # type: ignore # needs fixing
             return more
 
         self.set_capability(

tests/test_integ.py

@@ -68,3 +68,17 @@ def test_scan(root_window):
                 )
                 twain.global_handle_free(handle)
                 index += 1
+
+
+def test_acquire_natively(root_window):
+    """
+    Testing acquire_natively method
+    """
+    logger.info("creating source manager")
+    with twain.SourceManager(root_window) as sm:
+        logger.info("opening source")
+        with sm.open_source() as ss:  # this posts a modeless dialog...
+            logger.info("calling acquire_natively")
+            ss.acquire_natively(
+                after=lambda img, no: img.close()
+            )