Estimate the Taylor polynomial of f at x by polynomial fitting.
Parameters :  f : callable
x : scalar
degree : int
scale : scalar
order : int or None


Returns :  p : poly1d instance

Notes
The appropriate choice of “scale” is a tradeoff; too large and the function differs from its Taylor polynomial too much to get a good answer, too small and roundoff errors overwhelm the higherorder terms. The algorithm used becomes numerically unstable around order 30 even under ideal circumstances.
Choosing order somewhat larger than degree may improve the higherorder terms.