"""
This module provides basic examples of Python conventions and best practices.

Includes:
- Function definitions with appropriate naming and docstrings.
- Class definitions using CamelCase.
- Proper imports, whitespace, and error handling.
- A basic test using unittest.
"""

import math
import unittest

# Constants
PI = 3.14159

class CircleShape:
    """
    Class to represent a circle with a given radius.
    """
    
    def __init__(self, radius):
        """
        Initialize the CircleShape instance with a radius.
        
        Parameters:
        radius (float): The radius of the circle.
        """
        self.radius = radius

    def area(self):
        """
        Calculate the area of the circle.
        
        Returns:
        float: The area of the circle.
        """
        return PI * self.radius ** 2

def calculate_area(radius):
    """
    Calculate the area of a circle with the given radius.
    
    Parameters:
    radius (float): The radius of the circle.
    
    Returns:
    float: The area of the circle.
    """
    return PI * radius ** 2

def print_results(results):
    """
    Print a list of results, each on a new line.
    
    Parameters:
    results (list): The list of results to print.
    """
    for result in results:
        print(result)

def main():
    """
    Main function to demonstrate usage of the CircleShape class and functions.
    """
    radius = 5.0
    circle = CircleShape(radius)
    area = calculate_area(radius)
    print(f"The area of the circle with radius {radius} is {area}.")
    print("Results from CircleShape class:")
    print_results([circle.area()])

# Error Handling Example
def divide_numbers(a, b):
    """
    Divide two numbers with error handling for division by zero.
    
    Parameters:
    a (float): The numerator.
    b (float): The denominator.
    
    Returns:
    float: The result of the division.
    """
    try:
        # Attempt to convert inputs to integers
        num1 = int(a)
        num2 = int(b)
        
        # Attempt to divide num1 by num2
        result = num1 / num2
        
        return result
    
    except ValueError as ve:
        # Handle case where conversion to integer fails
        print(f"ValueError: Invalid input. Please provide valid integers. Details: {ve}")
        return None
    
    except ZeroDivisionError as zde:
        # Handle case where division by zero occurs
        print(f"ZeroDivisionError: Cannot divide by zero. Details: {zde}")
        return None
    
    except Exception as e:
        # Handle any other unexpected errors
        print(f"Unexpected error occurred: {e}")
        return None

# Unit Tests
class TestCircleShape(unittest.TestCase):
    
    def test_area(self):
        "Test the area calculation."
        circle = CircleShape(3)
        self.assertAlmostEqual(circle.area(), PI * 3 ** 2)
    
    def test_divide_numbers(self):
        "Test division with error handling."
        self.assertEqual(divide_numbers(10, 2), 5)
        self.assertIsNone(divide_numbers(10, 0))
        self.assertIsNone(divide_numbers("ten", 2))

if __name__ == "__main__":
    main()
    unittest.main()