fix bug

@@ -313,6 +313,8 @@ class BSWorkbook(Workbook):
 
     @staticmethod
     def rm_cn_char(row_value, pre_col, next_col):
+        if len(row_value) <= next_col:
+            return row_value
         row_value = list(row_value)
         if isinstance(row_value[pre_col], str):
             cn_chars = re.findall(consts.CN_RE, row_value[pre_col])
@@ -335,7 +337,7 @@ class BSWorkbook(Workbook):
             max_idx = amount_cell_idx
         else:
             max_idx = 0
-        if max_idx > 1:
+        if 1 < max_idx < len(row_value):
             append_list = []
             for i in range(2, max_idx+1):
                 if isinstance(row_value[i], str):