fix bug

@@ -373,7 +373,7 @@ class Command(BaseCommand, LoggerMixin):
                 # 4.获取OCR结果并且构建excel文件
                 bs_summary = {}
                 license_summary = {}
-                unknown_summary = []
+                unknown_summary = {}
                 interest_keyword = Keywords.objects.filter(
                     type=KeywordsType.INTEREST.value).values_list('keyword', flat=True)
                 salary_keyword = Keywords.objects.filter(

@@ -169,6 +169,10 @@ class BSWorkbook(Workbook):
                     0, (ws.title, idx_list[-1] + min_row, ws.max_row, 0))
 
     def build_metadata_rows(self, classify, confidence, role, code, print_time, start_date, end_date):
+        if start_date is None or end_date is None:
+            timedelta = None
+        else:
+            timedelta = (end_date - start_date).days
         metadata_rows = [
             ('流水识别置信度', confidence),
             self.blank_row,
@@ -182,7 +186,7 @@ class BSWorkbook(Workbook):
         metadata_rows.extend(
             [self.blank_row,
              self.date_header,
-             (print_time, start_date, end_date, (end_date - start_date).days),
+             (print_time, start_date, end_date, timedelta),
              self.blank_row,
              self.keyword_header]
         )