Allow for more lenient unions

src/coscine/metadata.py

@@ -685,19 +685,17 @@ class QueryResult:
     
     def union(self, files: list[FileObject], attribute: property, column: str) -> list[FileObject]:
         """
+        Computes the union between a list of files, a file (coscine.FileObject)
+        property and the property reflected in the SPARQL query result
+        identified via the column it appears in.
         """
         result = []
         column_index = self.headers.index(column)
         for row in self.rows:
-            found = False
             for f in files:
                 if f.match(attribute, row[column_index]):
                     result.append(f)
-                    found = True
                     break
-            if not found:
-                print(f"Not found for {row[column_index]}")
-        assert len(result) == len(self.rows)
         return result
 
     def files(self, column: int) -> list[FileObject]: