call fitz.close() after processing

plakativ.py

@@ -2005,6 +2005,7 @@ option""",
     plakativ = Plakativ(doc, pagenr)
     plakativ.compute_layout(mode, size, mult, npages, pagesize, border, strategy)
     plakativ.render(outfile, cover, guides, numbers, poster_border)
+    doc.close()
 
 
 def gui(filename=None):

plakativ_test.py

@@ -172,6 +172,7 @@ def test_cases(postersize, input_pagesize, output_pagesize, strategy, expected):
     )
     os.close(fd)
     doc.save(infile, pretty=True, expand=255)
+    doc.close()
 
     fd, outfile = tempfile.mkstemp(prefix="plakativ")
     os.close(fd)