Fix psf/black issues than fail the build (#1935)

* Fix psf/black issues than fail the build

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

data_structures/stacks/stack.py

@@ -46,11 +46,11 @@ class Stack:
     def size(self):
         """ Return the size of the stack."""
         return len(self.stack)
-    
+
     def __contains__(self, item) -> bool:
         """Check if item is in stack"""
         return item in self.stack
-    
+
 
 class StackOverflowError(BaseException):
     pass
@@ -73,4 +73,3 @@ if __name__ == "__main__":
     num = 5
     if num in stack:
         print(f"{num} is in stack")
-