CLN blacken first 15 notebooks

[MarcoGorelli]

xref #4095

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[codecov]

Codecov Report

Merging #4148 into master will decrease coverage by 0.11%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4148      +/-   ##
==========================================
- Coverage   88.74%   88.63%   -0.12%     
==========================================
  Files          89       89              
  Lines       14024    14466     +442     
==========================================
+ Hits        12446    12822     +376     
- Misses       1578     1644      +66     

Impacted Files	Coverage Δ
pymc3/distributions/simulator.py	82.85% <0.00%> (-2.63%)	⬇️
pymc3/step_methods/elliptical_slice.py	94.33% <0.00%> (-0.79%)	⬇️
pymc3/step_methods/gibbs.py	39.65% <0.00%> (-0.35%)	⬇️
pymc3/step_methods/sgmcmc.py	0.00% <0.00%> (ø)
pymc3/variational/__init__.py	100.00% <0.00%> (ø)
pymc3/distributions/special.py	100.00% <0.00%> (ø)
pymc3/distributions/discrete.py	96.98% <0.00%> (ø)
pymc3/step_methods/metropolis.py	88.27% <0.00%> (ø)
pymc3/step_methods/step_sizes.py	100.00% <0.00%> (ø)
pymc3/distributions/shape_utils.py	100.00% <0.00%> (ø)
... and 13 more

[AlexAndorra]

All good, thanks @MarcoGorelli !