smichr/sympy — comment on commit 0b9d43b643ffa6e31ae1d7dc9f7f735c40a75b5b
File: sympy/core/expr.py line 2009
By smichr:

This has been reworded as:

The _eval_nseries method should be added to
%s to give terms up to O(x**n) at x=0
from the positive direction so it is available when
nseries calls it.""" % self.func)
)