Python Institute PCPP1 – Certified Professional in Python Programming 1 (PCPP-32-101)

✅

Reasoning: Composition represents a "has-a" relationship, where one class holds instances of other classes as its members. This effectively means the composite class acts as a container, encapsulating and utilizing the functionalities of its contained objects. ❌ Why the other choices are incorrect:

• Option A is incorrect: Composition adds components (extending capabilities) but does not inherently modify the existing components of the enclosing class. It assembles, rather than alters, its own structure based on contained objects.
• Option C is incorrect: While composition promotes reusability, inheritance primarily promotes reusability (of base class implementation) and polymorphism. Encapsulation is a core OOP principle, not uniquely promoted by inheritance over composition; both can be used to maintain it.
• Option D is incorrect: Composition is indeed based on "has-a." However, composition and inheritance ("is-a") are not mutually exclusive; they are often used together in complex designs to achieve robust object relationships.

✅

Reasoning: Python mandates that any object raised as an exception must be an instance of a class that inherits, directly or indirectly, from BaseException. The OwnMath class, as defined, does not inherit from Exception or BaseException. Therefore, attempting to raise OwnMath("Cannot divide by zero!") will result in a TypeError (specifically, "exceptions must derive from BaseException"). This TypeError is then caught by the except Exception as e: block. ❌ Why the other choices are incorrect:

• Option A is incorrect: Implicit exception chaining occurs when an exception is raised inside an except or finally block, or when an unhandled exception occurs and another is raised. The issue here is a TypeError due to an invalid raise statement, not chaining.
• Option C is incorrect: The script execution is interrupted. A TypeError is raised when the raise OwnMath(...) statement is executed, and this exception is subsequently caught by the general except Exception block.
• Option D is incorrect: Explicit exception chaining uses the raise... from... syntax to link exceptions, which is not present in this code snippet.

✅

Reasoning: Inside the __init__ method, self.name = 'Excalibur' assigns the string value 'Excalibur' to the name attribute of the specific instance (self). Thus, 'Excalibur' is the value assigned to an instance variable. ❌ Why the other choices are incorrect:

• Option A is incorrect: self.name refers to an instance variable, not a class variable. Class variables are defined directly within the class body, outside any methods.
• Option B is incorrect: var1 is defined within the class scope, making it a class variable. Global variables are defined at the module level.
• Option D is incorrect: 'weapon' is the value assigned to var1, which is a class variable, not an instance variable.

✅ **Polymorphism **

Reasoning: Polymorphism, specifically duck typing, is demonstrated. Different object types (A and C) respond to the same method call (element.run) in their own distinct ways. The loop attempts to use a common interface across varied objects. ❌ Why the other choices are incorrect:

• Option A is incorrect: Serialization involves converting an object's state into a storable/transmittable format, which is not depicted.
• Option B is incorrect: Inheritance requires classes to derive properties/methods from a base class; no such relationship exists here.
• Option C is incorrect: Encapsulation focuses on bundling data with methods that operate on it and restricting direct access. This snippet doesn't primarily illustrate data hiding.

✅ **Reasoning: The function is erroneous because our_function is called inside level2_wrapper but is never defined in any accessible scope. This will result in a NameError when the decorated function is executed. ❌ Why the other choices are incorrect:

• Option A is incorrect: While my_decorator(coating) structurally allows arguments, the internal implementation error makes the statement misleading as the best**
  

  
  

  ---

  ✅ Analysis:

  .
• Option B is incorrect: The code defines a single decorator. Decorator stacking involves applying multiple decorators to a target function, which this code example does not illustrate.
• Option C is incorrect: The error is an undefined name, not infinite recursion. The our_function call would raise a NameError before any potential recursive behavior could occur.

✅

Reasoning: The function def f1 (*arg, **args): uses valid Python syntax for defining functions with variable positional (*arg) and variable keyword (**args) arguments. While *args and **kwargs are standard conventions, using *arg and **args as parameter names is syntactically allowed and does not cause an error. ❌ Why the other choices are incorrect:

• Option B is incorrect: The *arg parameter collects variable positional arguments into a tuple, not a list. Python's variable argument syntax *parameter_name always creates a tuple.
• Option C is incorrect: The *arg parameter explicitly serves as the placeholder for collecting any number of unnamed (positional) parameters. It is present and correctly defined.
• Option D is incorrect: The code is syntactically correct. Python allows developers to choose arbitrary valid identifier names for variable positional and keyword parameters; *args and **kwargs are conventions, not strict syntax requirements.

✅

Reasoning: The getNumberOfCrosswords(cls) method clearly accesses a class variable (cls.number_of_Crosswords) and is designed to operate on the class itself, indicated by the cls parameter. Such methods must be decorated with @classmethod. ❌ Why the other choices are incorrect:

• Option A is incorrect: The presence of one initializer does not preclude the need for class methods, especially when a method specifically operates on class-level data.
• Option C is incorrect: While the isElementCorrect method is erroneous (a staticmethod attempting to call an instance method via self), option B provides a specific, correct solution for another method, addressing the "which method should be distinguished as a class method" part of the question.
• Option D is incorrect: The isSolved(self) method accesses an instance attribute (self.progress), making it an instance method, not a class method.

✅

Reasoning: The special method __ne__ in Python is specifically designed to overload the "not equal to" operator (!=). Therefore, code implementing or describing __ne__ is responsible for defining how objects compare for inequality. ❌ Why the other choices are incorrect:

• Option A is incorrect: __ne__ is a built-in special method (a dunder method) in Python, used for operator overloading.
• Option B is incorrect: Without the specific code, assuming it's erroneous is speculative. __ne__ itself is a valid method.
• Option C is incorrect: The negation operator (unary minus, -) is handled by the __neg__ special method, not __ne__
   

Reference: https://docs.python.org/3/reference/datamodel.html#object.__ne__