<!DOCTYPE qhelp PUBLIC

"-//Semmle//qhelp//EN"

"qhelp.dtd">

<qhelp>

<overview>

<p>All functions in Python return a value.

If a function has no <code>return</code> statements or none of the <code>return</code> statements return a value

then the function will return <code>None</code>. However, this value has no meaning and should be ignored.</p>

<p>Using the return value of such a 'procedure' is confusing to the reader as it suggests

that the value is significant.

</p>

</overview>

<recommendation>

<p>Do not use the return value of a procedure; replace <code>x = proc()</code> with <code>proc()</code>

and replace any use of the value with <code>None</code>.</p>

</recommendation>

<example>

<p>In this example, the <code>my_print</code> function is a procedure as it returns no value of any meaning.

Using the return value is misleading in subsequent code.

</p>

<sample src="UseImplicitNoneReturnValue.py" />

</example>

<references>

<li>Python Library Reference: <a href="http://docs.python.org/library/constants.html#None">None</a>.</li>

</references>

</qhelp>