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<H2><A NAME="SECTION004260000000000000000">
2.2.6 More Suggestions</A>
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<P>
Remember that you can omit most of these functions, in which case you
provide <code>0</code> as a value.  There are type definitions for each of
the functions you must provide.  They are in <span class="file">object.h</span> in the
Python include directory that comes with the source distribution of
Python.

<P>
In order to learn how to implement any specific method for your new
data type, do the following: Download and unpack the Python source
distribution.  Go the <span class="file">Objects</span> directory, then search the
C source files for <code>tp_</code> plus the function you want (for
example, <code>tp_print</code> or <code>tp_compare</code>).  You will find
examples of the function you want to implement.

<P>
When you need to verify that an object is an instance of the type
you are implementing, use the <tt class="cfunction">PyObject_TypeCheck</tt> function.
A sample of its use might be something like the following:

<P>
<div class="verbatim"><pre>
    if (! PyObject_TypeCheck(some_object, &amp;MyType)) {
        PyErr_SetString(PyExc_TypeError, "arg #1 not a mything");
        return NULL;
    }
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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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