Refactor. (#4487)

### What problem does this PR solve?

### Type of change

- [x] Refactoring

deepdoc/parser/resume/entities/corporations.py

@@ -44,7 +44,7 @@ def baike(cid, default_v=0):
 
 def corpNorm(nm, add_region=True):
     global CORP_TKS
-    if not nm or isinstance(nm, str):
+    if not nm or not isinstance(nm, str):
         return ""
     nm = rag_tokenizer.tradi2simp(rag_tokenizer.strQ2B(nm)).lower()
     nm = re.sub(r"&", "&", nm)