sage -t --long --random-seed=185470747385175316039405094141387664605 src/doc/en/thematic_tutorials/group_theory.rst
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File "src/doc/en/thematic_tutorials/group_theory.rst", line 207, in doc.en.thematic_tutorials.group_theory
Failed example:
    euler_phi(m*n) == euler_phi(m) * euler_phi(n)
Expected:
    True
Got:
    False
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1 item had failures:
   1 of 170 in doc.en.thematic_tutorials.group_theory
    [127 tests, 1 failure, 4.40 s]