Add example for __add__ dunder method in README.md and implement corresponding example script

Author: andrelbd1

python_utils/dunder_methods/README.md

@@ -9,6 +9,9 @@
 ##### `__lt__`
 - [Comparison for less-than operation](__lt__1.py)
 
+##### `__add__`
+- [Adding objects with the `+` operator](__add__1.py)
+
 ##### `__format__`
 - [Custom string formatting](__format__1.py)
 - [Custom string formatting](__format__2.py)

python_utils/dunder_methods/__add__1.py

@@ -0,0 +1,21 @@
+from typing import Self
+
+
+class Fruit:
+    def __init__(self, *, name: str, grams: float) -> None:
+        self.name = name
+        self.grams = grams
+
+    def __add__(self, other: Self) -> bool:
+        return self.grams + other.grams
+
+
+def main() -> None:
+    f1: Fruit = Fruit(name='Apple', grams=100)
+    f2: Fruit = Fruit(name='Banana', grams=150)
+
+    print(f1 + f2)  # 250
+
+
+if __name__ == '__main__':
+    main()