# [Python 2], 75 bytes

<!-- language-all: lang-python -->

 def f(s):len({2<<s.count(c)-2for c,in s})>1<{{ddeiillorrttuu:-1.>>-2.,}:1,}

Output is via [presence or absence of an error.][meta] The error is either a *ValueError* (one or more characters occur only once) or a *TypeError* (the character counts are unequal).

[Try it online!][TIO-je98l5wq]

[Python 2]: https://docs.python.org/2/
[meta]: https://codegolf.meta.stackexchange.com/a/11908/12012
[TIO-je98l5wq]: https://tio.run/##XY/nzqJQEIZ/61UcPwugiIIde@@961rxoCgCwsHutbtosrvJTjJ98kxe5YZ2ssS8OXkDQRxgGPbeQB7wuEawIpTwBxOLaRQn6xLCOcLN8LIKOFKQgPYiEnTs8dhsoCCIoqyqCOk666apRMLNUOSLpcnX2@BRGlIFBSfMZniFHPg8MpsvO0GEoKfqkDWbkHozoonHBUnREU4QRqOogoS@B2YTvHJQQSDfLORVVVbZv2vsl9SFIg8Q1BCLkV/Gh/8/wKSuBA2C7k1D8Ji/CugP8x@qsBI1@P5ZGfZjNpKFBjSwrICF/rbrNccZSiHPb7fGgG5bBgu@K6SDGVV4PF/okKvPBvtGJT5f@PGVI54MyOMVSV92z45/XO0Da4SzWNug5@CXrHa0pUZnt74dxlqE@Bq2EgVsL/quxw0WKUNbvRHtqdlM1oMm5ZqzyITWt7xEbb2H6m7dsSeKbiqglLial6hMlhrrnF6Z7j0Ytp/nJTnsmkLy0UyfpKQvH2sWLiM8mrrpM9c95FE2p37uo@Xj6/VH0rfijLhu88Eulw5sWP9iVSFyM8Y5r5/x/Ku6Dsmp2UGF52ES9ryFYbT8rLDCFdgjFl/hcow6@5NiaRlGg8T2Rl9Hsa6nmQ41UAZ7cUDHBrYaORbHysM6pai9Y9s7hPeKO9gRi/2adRGbe7PZSbXV5nOMXSN20J2pd3RaSp42gscSOMUvkk1WV64R2Wre76XGLo77H8elL1J@alNXPuW4JX5@Aw "Python 2 – Try It Online"