removed unused packages

tools/read_hist.py

 import numpy as np
 import matplotlib.pyplot as plt
 import boost_histogram as bh
-import operator
-import functools
 
 def read_hist(filename):
     """
@@ -14,14 +12,14 @@ def read_hist(filename):
     axistypes = d['axistypes'].view('c')
     overflow = d['overflow']
     underflow = d['underflow']
-    
+
     axes = []
     for i, (at, has_overflow, has_underflow) in enumerate(zip(axistypes, overflow, underflow)):
         if at == b'c':
             axes.append(bh.axis.Variable(d[f'binedges_{i}'], overflow=has_overflow, underflow=has_underflow))
         elif at == b'd':
             axes.append(bh.axis.IntCategory(d[f'bins_{i}'], growth=(not has_overflow)))
-        
+ 
     h = bh.Histogram(*axes)
     h.view(flow=True)[:] = d['data']