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The "raise from" function in Python is used to raise an exception with a cause. This is useful when one error leads to another error, and you want to indicate the root cause of the error rather than just the immediate cause.

Here's an example:

try:
    # some code that may raise an exception
except Exception as e:
    # handle the exception
    raise ValueError("An error occurred") from e

In this example, if the code inside the try block raises an exception, the except block will catch it and handle it. However, instead of just raising a ValueError with the message "An error occurred", we use the "raise from" syntax to indicate that the immediate cause of the error was the original exception caught in the except block. This way, the traceback will show both the immediate cause and the root cause of the error.