Documentation officielle de Python

5.19.2 Subclassing Repr Objects

The use of dynamic dispatching by Repr.repr1() allows subclasses of Repr to add support for additional built-in object types or to modify the handling of types already supported. This example shows how special support for file objects could be added:

import repr
import sys

class MyRepr(repr.Repr):
    def repr_file(self, obj, level):
        if obj.name in ['<stdin>', '<stdout>', '<stderr>']:
            return obj.name
        else:
            return `obj`

aRepr = MyRepr()
print aRepr.repr(sys.stdin)          # prints '<stdin>'

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