Do not split data file to be used by other methods

wizard/account_bank_statement_import.py

@@ -89,8 +89,8 @@ class AccountBankStatementImport(models.TransientModel):
 
     @api.model
     def _parse_file(self, data_file):
-        data_file = data_file.splitlines()
-        result = self._check_file(data_file)
+        data_file_split = data_file.splitlines()
+        result = self._check_file(data_file_split)
         if not result:
             return super(AccountBankStatementImport, self)._parse_file(
                 data_file)
@@ -100,7 +100,7 @@ class AccountBankStatementImport(models.TransientModel):
         total_amt = 0.00
         try:
             index = 0
-            for line in data_file[5:len(data_file)-1]:
+            for line in data_file_split[5:len(data_file_split)-1]:
                 transaction = re.compile(self.regexp_version[file_version]['line_debit']).search(line)
                 if (transaction != None):
                     transaction_amount = float(transaction.group('debit').replace(',','.'))