Use pop rather than del

Co-authored-by: jakirkham <[email protected]>

Author: joshmoore

zarr/n5.py

@@ -311,11 +311,7 @@ def group_metadata_to_n5(group_metadata):
 
 def group_metadata_to_zarr(group_metadata):
     '''Convert group metadata from N5 to zarr format.'''
-    try:
-        del group_metadata['n5']
-    except KeyError:
-        # This only exists at the top level
-        pass
+    group_metadata.pop('n5')
     group_metadata['zarr_format'] = ZARR_FORMAT
     return group_metadata