Clean up unused function

tetras_extraction/script/src/extract.py

-import filecmp
-
 from lxml import etree
 from rdflib import RDFS, Graph, Literal, URIRef
 from rdflib.namespace import OWL, RDF
@@ -146,14 +144,6 @@ def is_subsection(id: str):
     )
 
 
-def compare_files(f1: str, f2: str):
-    log.info(
-        "Files {} and {} {}.".format(
-            f1, f2, "are identical" if filecmp.cmp(f1, f2) else "differ"
-        )
-    )
-
-
 def main():
     g = create_graph()