Python - detect when my object is written to stdout?

Question

I have a rather unusual request, I think... I\'ll explain the why after I explain the what.

What

I want to detect whenever my object is written

Answer 1

Why not monkeypatch stdout.write?

stdoutRegistry = set()

class A(object):
    def __init__(self):
        self.stdoutRegistry.add(self)

    def stdoutNotify(self):
        pass

original_stdoutWrite = sys.stdout.write
def stdoutWrite(*a, **kw):
    if a in stdoutRegistry:
        a.stdoutNotify()
    original_stdoutWrite(*a, **kw)
sys.stdout.write = stdoutWrite