Created Planet class in planets.py

app/__init__.py

@@ -3,5 +3,8 @@
 
 def create_app(test_config=None):
     app = Flask(__name__)
+
+    from .planets import planets_bp
+    app.register_blueprint(planets_bp)
 
     return app

app/planets.py

@@ -0,0 +1,49 @@
+from flask import Blueprint, jsonify, abort, make_response
+
+class Planet():
+    def __init__(self, id, name, description):
+        self.id = id
+        self.name = name
+        self.description = description
+
+    def to_dict(self):
+        return   {
+                "id": self.id,
+                "name": self.name,
+                "description": self.description
+            }
+
+
+planets = [
+    Planet(id = 3, name = "Earth", description = "habitable"),
+    Planet(id = 1, name = "Mercury", description = "inhabitable"),
+    Planet(id = 4, name = "Mars", description = "inhabitable")
+]
+
+def validate_planet(planet_id):
+    try:
+        planet_id = int(planet_id)
+    except:
+        abort(make_response({"message": f"Planet {planet_id} is not an int."}, 400))
+
+    for planet in planets:
+        if planet.id == planet_id:
+            return planet
+
+    abort(make_response({"message":f"planet {planet_id} not found"}, 404))
+
+
+planets_bp = Blueprint("planets_bp", __name__, url_prefix="/planets")
+
+@planets_bp.route("", methods=["GET"])
+def get_all_planets():
+    planet_response = []
+    for planet in planets:
+        planet_response.append(planet.to_dict())
+
+    return jsonify(planet_response)
+
+@planets_bp.route("/<planet_id>", methods=["GET"])
+def get_planet_by_id(planet_id):
+    planet = validate_planet(planet_id)
+    return jsonify(planet.to_dict())