raise custom exception in python

Title: A Guide to Creating and Handling Custom Exceptions in Python
Introduction:
Exceptions in Python provide a way to handle errors and unexpected situations in a program. While Python comes with a set of built-in exceptions, sometimes it's necessary to create custom exceptions that suit the specific needs of your application. In this tutorial, we'll explore how to raise and handle custom exceptions in Python.
Creating a Custom Exception:
To create a custom exception, you need to define a new class that inherits from the built-in Exception class. Here's a simple example:
In this example, CustomError is a custom exception class that inherits from Exception. It has an optional message parameter, and the __init__ method initializes the exception with the given message.
Raising Custom Exceptions:
You can raise your custom exception using the raise keyword. Let's see how to use our CustomError:
In this example, if the value parameter is negative, a CustomError will be raised with the specified message.
Handling Custom Exceptions:
To handle custom exceptions, you can use a try and except block. Here's an example:
In this example, the try block attempts to execute example_function(-5). Since it raises a CustomError, the control moves to the except block where you can handle the exception as needed.
Adding Custom Attributes:
You can add custom attributes to your exception for more detailed information. Modify the CustomError class as follows:
Now, when you raise the exception, you can provide additional information:
Best Practices:
By following these steps, you can create and handle custom exceptions in Python, improving the clarity and maintainability of your code.
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