The following code produces an OverflowError:

import statistics
statistics.mean([8.988465674311579e+307, 8.98846567431158e+307])

The error is:

  File "/home/david/.pyenv/versions/3.5.0/lib/python3.5/statistics.py", line 293, in mean
    return _sum(data)/n
  File "/home/david/.pyenv/versions/3.5.0/lib/python3.5/statistics.py", line 184, in _sum
    return T(total)
  File "/home/david/.pyenv/versions/3.5.0/lib/python3.5/numbers.py", line 291, in __float__
    return self.numerator / self.denominator
OverflowError: integer division result too large for a float


If this is intended behaviour then it is not documented: https://docs.python.org/3/library/statistics.html#statistics.mean only specifies that it may raise StatisticsError.