A 'KeyError' occurs when trying to access a key that doesn’t exist in a dictionary. Use the `in` keyword to check for the key's existence before accessing it, or use the `get()` method to provide a default value.

The 'KeyError' in Python is a common exception encountered when attempting to access a dictionary key that does not exist. This can happen when you assume a key is present without verifying it, leading to program crashes. To effectively handle KeyErrors, first, check if the key exists in the dictionary using the in keyword. For example, you can use if key in my_dict: before accessing my_dict[key]. Alternatively, you can utilize the get() method, which allows you to specify a default return value if the key is not found. For instance, value = my_dict.get(key, default_value) will return default_value instead of raising a KeyError. Using these techniques not only prevents errors but also allows for more robust and user-friendly code. Additionally, consider using exception handling with a try-except block to manage KeyErrors gracefully, providing fallback logic or informative error messages to the user. By implementing these strategies, you can effectively deal with KeyErrors in your Python applications.