def pdef(self, obj, oname=''):
        """Print the definition header for any callable object.

        If the object is a class, print the constructor information."""

        if not callable(obj):
            print 'Object is not callable.'
            return

        header = ''

        if inspect.isclass(obj):
            header = self.__head('Class constructor information:\n')
            obj = obj.__init__
        elif (not py3compat.PY3) and type(obj) is types.InstanceType:
            obj = obj.__call__

        output = self._getdef(obj,oname)
        if output is None:
            self.noinfo('definition header',oname)
        else:
            print >>io.stdout, header,self.format(output),