No module named 'sklearn.externals.joblib' ERROR

Question

I am trying to implement a Bayesian optimization but already starting having an error while importing 'gp_minimize' from scikit-optimize package from skopt import gp_minimize

res = gp_minimize(f,                  # the function to minimize
                  [(-2.0, 2.0)],      # the bounds on each dimension of x
                  acq_func="EI",      # the acquisition function
                  n_calls=15,         # the number of evaluations of f
                  n_random_starts=5,  # the number of random initialization points
                  noise=0.1**2,       # the noise level (optional)
                  random_state=1234)   # the random seed*
---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-13-8761d45476ed> in <module>
----> 1 from skopt import gp_minimize
      2 
      3 res = gp_minimize(f,                  # the function to minimize
      4                   [(-2.0, 2.0)],      # the bounds on each dimension of x
      5                   acq_func="EI",      # the acquisition function

~\Anaconda3\lib\site-packages\skopt\__init__.py in <module>
     50 from . import benchmarks
     51 from . import callbacks
---> 52 from . import learning
     53 from . import optimizer
     54 

~\Anaconda3\lib\site-packages\skopt\learning\__init__.py in <module>
      4 from .forest import ExtraTreesRegressor
      5 from .gaussian_process import GaussianProcessRegressor
----> 6 from .gbrt import GradientBoostingQuantileRegressor
      7 
      8 

~\Anaconda3\lib\site-packages\skopt\learning\gbrt.py in <module>
      5 from sklearn.ensemble import GradientBoostingRegressor
      6 from sklearn.utils import check_random_state
----> 7 from sklearn.externals.joblib import Parallel, delayed
      8 
      9 

ModuleNotFoundError: No module named 'sklearn.externals.joblib'

I already downloaded all required packages such joblib and scikit learn and scikit optimize, so I can't figure out why it's not working.

Answer 1

Solution = Finally, I reinstalled Anaconda et scikit-optimizer again and all worked.