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<H1><A NAME="SECTION005300000000000000000"></A>
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3.3 Special method names
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<P>
A class can implement certain operations that are invoked by special
syntax (such as arithmetic operations or subscripting and slicing) by
defining methods with special names.  For instance, if a class defines
a method named <tt class=method>__getitem__()</tt>, and <tt>x</tt> is an instance of
this class, then <tt>x[i]</tt> is equivalent to
<tt>x.__getitem__(i)</tt>.  (The reverse is not true -- if <tt>x</tt> is
a list object, <tt>x.__getitem__(i)</tt> is not equivalent to
<tt>x[i]</tt>.)  Except where mentioned, attempts to execute an
operation raise an exception when no appropriate method is defined.
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