A 'KeyError' in Python occurs when you try to access a dictionary with a key that does not exist. Check if the key is spelled correctly or use the .get() method to handle missing keys gracefully.

The 'KeyError' is a common exception that arises when attempting to access a key in a dictionary that is not present. Since dictionaries in Python are unordered collections of key-value pairs, each key must be unique, and attempting to access a non-existent key will result in a KeyError. To troubleshoot this error, first, verify that the key you're trying to access is indeed present in the dictionary. This can be done by printing the dictionary keys using the .keys() method or simply converting the dictionary to a list of keys. If you're unsure whether a key exists, consider using the dict.get() method, which allows you to specify a default value to return if the key is not found. This approach prevents KeyErrors and can lead to more robust code. Additionally, implementing proper error handling with try-except blocks can help you manage these situations gracefully. By employing these strategies, you can effectively manage KeyErrors and improve the reliability of your Python code when working with dictionaries.