[IMP] account_statement_import_sheet_file: add field amount_inverse_sign_column.

In some cases such as in credit card statements the amounts are expressed in the inverse sign.
By setting this flag during the upload the amounts will be inverted in sign.

account_statement_import_sheet_file/models/account_statement_import_sheet_mapping.py

@@ -79,6 +79,13 @@ class AccountStatementImportSheetMapping(models.Model):
         string="Credit amount column",
         help="Credit amount of transaction in journal's currency",
     )
+    amount_inverse_sign = fields.Boolean(
+        string="Inverse sign of amount",
+        help="In some cases such as in credit card statements the "
+        "amounts are expressed in the inverse sign. "
+        "By setting this flag during the upload the amounts "
+        "will be inverted in sign.",
+    )
     balance_column = fields.Char(
         help="Balance after transaction in journal's currency",
     )

account_statement_import_sheet_file/models/account_statement_import_sheet_parser.py

@@ -4,6 +4,7 @@
 
 import itertools
 import logging
+from collections.abc import Iterable
 from datetime import datetime
 from decimal import Decimal
 from io import StringIO
@@ -97,7 +98,11 @@ class AccountStatementImportSheetParser(models.TransientModel):
 
     def _get_column_indexes(self, header, column_name, mapping):
         column_indexes = []
-        if mapping[column_name] and "," in mapping[column_name]:
+        if (
+            mapping[column_name]
+            and isinstance(mapping[column_name], Iterable)
+            and "," in mapping[column_name]
+        ):
             # We have to concatenate the values
             column_names_or_indexes = mapping[column_name].split(",")
         else:
@@ -319,7 +324,6 @@ class AccountStatementImportSheetParser(models.TransientModel):
                 if columns["bank_account_column"]
                 else None
             )
-
             if currency != currency_code:
                 continue
 
@@ -342,7 +346,10 @@ class AccountStatementImportSheetParser(models.TransientModel):
                 ).copy_sign(amount)
             else:
                 original_amount = 0.0
-
+            if mapping.amount_inverse_sign:
+                amount = -amount
+                original_amount = -original_amount
+                balance = -balance if balance is not None else balance
             line = {
                 "timestamp": timestamp,
                 "amount": amount,