Как найти TypeError, если позиция не указана?

Я тестирую некоторые фрагменты кода, которые я нашел, но у меня возникли проблемы с определением ошибки.

Код:

import datetime as dt
from datetime import date
import pandas as pd
import pandas_datareader.data as web
import numpy as np
import time
import math
import scipy.optimize as optimize


start = dt.datetime(2016,12,1)
end = dt.datetime(2020,12,1)


tick = ['GOOG', 'AAPL', 'AMZN']


#pandas dataframe
data = web.DataReader(tick, 'yahoo', start, end)['Adj Close']
data = np.log(data/data.shift(1))


def sharpetest(wts, returns):
  weights = np.array(wts)
  port_return = np.sum(returns.mean() * weights) * 252
  port_vol = np.sqrt(np.dot(weights.T, np.dot(returns.cov() * 252, weights)))
  sharpe = port_return/port_vol
  sharpe = np.array(sharpe)
  return sharpe
  

num_assets = len(tick)

constraints = ({'type' : 'eq', 'fun': lambda x: np.sum(x) -1})
bounds = tuple((0,1) for x in range(num_assets))
args = (num_assets * [1./num_assets,], data)


optimal_sharpe=optimize.minimize(sharpetest,
                               args,
                               method = 'SLSQP',
                               bounds = bounds,
                               constraints = constraints)
print(optimal_sharpe)

Выход:

   /usr/local/lib/python3.9/site-packages/numpy/core/_asarray.py:83:
   VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences (which is a list- 
   or-tuple of lists-or-tuples-or ndarrays with different lengths or shapes) is deprecated. If 
   you meant to do this, you must specify 'dtype=object' when creating the ndarray
   return array(a, dtype, copy=False, order=order)
   TypeError: float() argument must be a string or a number, not 'list'

Как видите, строка, где TypeError не указана. Как найти ошибку?

Прошу прощения за такой элементарный вопрос.