diff --git a/quinn/dataframe_validator.py b/quinn/dataframe_validator.py
index c4b20a64..8c667803 100644
--- a/quinn/dataframe_validator.py
+++ b/quinn/dataframe_validator.py
@@ -1,7 +1,7 @@
-from __future__ import annotations
+from __future__ import annotations # noqa: I001
 
 import copy
-from typing import TYPE_CHECKING
+from typing import Any, Callable, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from pyspark.sql import DataFrame
@@ -36,14 +36,14 @@ def validate_presence_of_columns(df: DataFrame, required_col_names: list[str]) -
     error_message = f"The {missing_col_names} columns are not included in the DataFrame with the following columns {all_col_names}"
     if missing_col_names:
         raise DataFrameMissingColumnError(error_message)
-    
+
 def validate_schema(
-    required_schema: StructType, 
-    ignore_nullable: bool = False, 
-    _df: DataFrame = None
-) -> function:
+    required_schema: StructType,
+    ignore_nullable: bool = False,
+    _df: DataFrame = None,
+) -> Callable[[Any, Any], Any]:
     """Function that validate if a given DataFrame has a given StructType as its schema.
-    Implemented as a decorator factory so can be used both as a standalone function or as 
+    Implemented as a decorator factory so can be used both as a standalone function or as
     a decorator to another function.
 
     :param required_schema: StructType required for the DataFrame
@@ -59,10 +59,10 @@ def validate_schema(
     schema are not included in the DataFrame schema
     """
 
-    def decorator(func):
-        def wrapper(*args, **kwargs):
-            df = func(*args, **kwargs)
-            _all_struct_fields = copy.deepcopy(df.schema)
+    def decorator(func: Callable[..., DataFrame]) -> Callable[..., DataFrame]:
+        def wrapper(*args: object, **kwargs: object) -> DataFrame:
+            dataframe = func(*args, **kwargs)
+            _all_struct_fields = copy.deepcopy(dataframe.schema)
             _required_schema = copy.deepcopy(required_schema)
 
             if ignore_nullable:
@@ -73,22 +73,22 @@ def wrapper(*args, **kwargs):
                     x.nullable = None
 
             missing_struct_fields = [x for x in _required_schema if x not in _all_struct_fields]
-            error_message = f"The {missing_struct_fields} StructFields are not included in the DataFrame with the following StructFields {_all_struct_fields}"
+            error_message = f"The {missing_struct_fields} StructFields are not included in the DataFrame with the following StructFields {_all_struct_fields}" # noqa: E501
 
             if missing_struct_fields:
                 raise DataFrameMissingStructFieldError(error_message)
-            else:
-                print("Success! DataFrame matches the required schema!")
 
-            return df
+            print("Success! DataFrame matches the required schema!")
+
+            return dataframe
         return wrapper
 
     if _df is None:
         # This means the function is being used as a decorator
         return decorator
-    else:
-        # This means the function is being called directly with a DataFrame
-        return decorator(lambda: _df)()
+
+    # This means the function is being called directly with a DataFrame
+    return decorator(lambda: _df)()
 
 
 def validate_absence_of_columns(df: DataFrame, prohibited_col_names: list[str]) -> None: