26.4.1 Warning Categories
There are a number of built-in exceptions that represent warning categories. This categorization is useful to be able to filter out groups of warnings. The following warnings category classes are currently defined:
| Class | Description |
|---|---|
| Warning | This is the base class of all warning category classes. It is a subclass of Exception. |
| UserWarning | The default category for warn(). |
| DeprecationWarning | Base category for warnings about deprecated features. |
| SyntaxWarning | Base category for warnings about dubious syntactic features. |
| RuntimeWarning | Base category for warnings about dubious runtime features. |
| FutureWarning | Base category for warnings about constructs that will change semantically in the future. |
| PendingDeprecationWarning | Base category for warnings about features that will be deprecated in the future (ignored by default). |
| ImportWarning | Base category for warnings triggered during the process of importing a module (ignored by default). |
| UnicodeWarning | Base category for warnings related to Unicode. |
While these are technically built-in exceptions, they are documented here, because conceptually they belong to the warnings mechanism.
User code can define additional warning categories by subclassing one of the standard warning categories. A warning category must always be a subclass of the Warning class.
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Release 2.5, documentation updated on 19th September, 2006.