Add decorator for needed packages

decorators.py

@@ -0,0 +1,43 @@
+from functools import wraps
+
+installed_packages = []
+
+
+def install_package(pkg):
+    if pkg not in installed_packages:
+        installed_packages.append(pkg)
+        print(f"Installed: {pkg}")
+    else:
+        print(f"Already installed: {pkg}")
+
+
+def needs_packages(packages):
+    def inner_decorator(function):
+        @wraps(function)
+        def execution_wrapper(*args, **kwargs):
+            [install_package(package) for package in packages]
+            return function(*args, **kwargs)
+
+        return execution_wrapper
+
+    return inner_decorator
+
+
+@needs_packages(['vim', 'calc'])
+def add(z1, z2):
+    return z1 + z2
+
+
+@needs_packages(['calc', 'sed'])
+def sub(z1, z2):
+    return z1 - z2
+
+
+@needs_packages(['calc'])
+def bla(z1, z2):
+    return z1 / z2
+
+
+print(add(1, 2))
+print(sub(1, 2))
+print(bla(1, 2))