used extend to self.skills, del init in FullStackDeveloper

app/main.py

@@ -11,7 +11,7 @@ def learn_skill(self, skill: str) -> None:
 class FrontendDeveloper(SoftwareEngineer):
     def __init__(self, name: str) -> None:
         super().__init__(name)
-        self.skills = ["JavaScript", "HTML", "CSS"]
+        self.skills.extend(["JavaScript", "HTML", "CSS"])
 
     def create_awesome_web_page(self) -> str:
         print(f"{self.name} is creating a webpage...")
@@ -21,7 +21,7 @@ def create_awesome_web_page(self) -> str:
 class BackendDeveloper(SoftwareEngineer):
     def __init__(self, name: str) -> None:
         super().__init__(name)
-        self.skills = ["Python", "SQL", "Django"]
+        self.skills.extend(["Python", "SQL", "Django"])
 
     def create_powerful_api(self) -> str:
         print(f"{self.name} is creating an API...")
@@ -31,20 +31,14 @@ def create_powerful_api(self) -> str:
 class AndroidDeveloper(SoftwareEngineer):
     def __init__(self, name: str) -> None:
         super().__init__(name)
-        self.skills = ["Java", "Android studio"]
+        self.skills.extend(["Java", "Android studio"])
 
     def create_smooth_mobile_app(self) -> str:
         print(f"{self.name} is creating a mobile app...")
         return "Ads every three swipes"
 
 
 class FullStackDeveloper(FrontendDeveloper, BackendDeveloper):
-    def __init__(self, name: str) -> None:
-        FrontendDeveloper.__init__(self, name)
-        BackendDeveloper.__init__(self, name)
-        self.skills = list(set(FrontendDeveloper(name).skills
-                               + BackendDeveloper(name).skills))
-
     def create_web_application(self) -> None:
         print(f"{self.name} started creating a web application...")
         self.create_powerful_api()