Error in running the Elliott Fitting function

[scidam]

I think, you missed arithmetical symbol in (( fitting-abs_exp_fit )**2).sum()((len( abs_exp_fit )-len(p0))).

( fitting-abs_exp_fit )**2).sum() -- This is a numpy array. Further, you've used parenthesis: ( fitting-abs_exp_fit )**2).sum()(...).
That means you tried to call a numpy array.

You need to change your code to

s_sq = (( fitting-abs_exp_fit )**2).sum()<some symbol here>((len( abs_exp_fit )-len(p0)))

where <some symbol here> is either "/", "*", etc (or something else).