Fix the static types

sage_validation/file_validator/forms.py

 """Forms for the file_validator app."""
 
 import csv
-from collections.abc import Iterable, Sequence
+from collections.abc import Sequence
 from typing import ClassVar
 
 from django import forms
@@ -126,7 +126,7 @@ class CSVUploadForm(forms.Form):
             raise forms.ValidationError(msg)
 
     @staticmethod
-    def _validate_source_and_trader_type(data: Iterable[dict]) -> list:
+    def _validate_source_and_trader_type(data: list[dict]) -> list:
         """Validate that 'Source' is always 80 and 'SYSTraderTranType' is always 4."""
         errors = []
 
@@ -140,14 +140,14 @@ class CSVUploadForm(forms.Form):
         return errors
 
     @staticmethod
-    def _validate_nominal_analysis_account(data: Iterable[dict]) -> list[str]:
+    def _validate_nominal_analysis_account(data: list[dict]) -> list[str]:
         """Validate that 'AccountNumber' matches the name in 'NominalAnalysisNominalAnalysisNarrative/1'.
 
         This only checks the first group of NominalAnalysis columns. A list of codes/names
         is fetched from the database for validation (from the 'PL Account Codes' table).
 
         Args:
-            data (Iterable[dict]): The rows of data to validate.
+            data (list[dict]): The rows of data to validate.
 
         Returns:
             List[str]: A list of error messages, if any.
@@ -180,14 +180,14 @@ class CSVUploadForm(forms.Form):
         return errors
 
 
-    def _validate_nc_cc_dep_combination_against_meo_sage_account(self, data: Iterable[dict]) -> list[str]:
+    def _validate_nc_cc_dep_combination_against_meo_sage_account(self, data: list[dict]) -> list[str]:
         """Validate that all nominal analysis fields exist in MEO.
 
         This includes 'NominalAnalysisNominalCostCentre/{N}', 'NominalAnalysisNominalDepartment/{N}',
         and 'NominalAnalysisNominalAccountNumber/{N}'.
 
         Args:
-            data (Iterable[dict]): The rows of data to validate.
+            data (list[dict]): The rows of data to validate.
 
         Returns:
             List[str]: A list of error messages, if any.