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<overview>

<p>In Python 2, if a tuple is raised then all elements but the first are ignored and only the first part is raised.

If the first element is itself a tuple, then the first element of that is used and so on.

This unlikely to be the intended effect and will most likely indicate some sort of error.</p>

<p>It is important to note that the exception in <code>raise Exception, message</code> is <em>not</em> a tuple, whereas the exception

in <code>ex = Exception, message; raise ex</code> <em>is</em> a tuple.</p>

<p>

In Python 3, raising a tuple is an error.

</p>

</overview>

<recommendation>

<p>Given that all but the first element of the tuple is ignored,

the tuple should be replaced with its first element in order to

improve the clarity of the code. If the subsequent parts of the tuple

were intended to form the message, then they should be passed as an argument

when creating the exception.

</p>

</recommendation>

<example>

<p>In the following example the intended error message is mistakenly used to form a tuple.</p>

<sample src="RaisingTuple.py" />

<p>This can be fixed, either by using the message to create the exception or using the message in the raise

statement, as shown below.</p>

<sample src="RaisingTuple2.py" />

</example>

<references>

<li>Python Language Reference: <a href="https://docs.python.org/reference/executionmodel.html#exceptions">Exceptions</a>.</li>

<li>Python Tutorial: <a href="https://docs.python.org/tutorial/errors.html#handling-exceptions">Handling Exceptions</a>.</li>

</references>

</qhelp>