linear_response.py FAILED! -> 'pylab' has no attribute 'poly_between'

[rwexler]

FYI: pylab.poly_between has been removed in matplotlib 3.1.1

Throws the following error when I run the tests:

C6H6_wedge.py             OK. (3.0 seconds)
[0.00447103 0.00447103 0.00968666 0.01300298 0.01344216 0.01344216
 0.0215762  0.0215762  0.03671848 0.07467506 0.07467507]
Traceback (most recent call last):
  File "/Users/robertwexler/hb/hotbit/lib/python/hotbit/test/linear_response.py", line 18, in <module>
    lr.plot_spectrum('Na3+_lr.png',width=0.08)
  File "/Users/robertwexler/hb/hotbit/lib/python/hotbit/analysis/lr.py", line 251, in plot_spectrum
    xs, ys = pl.poly_between(e, 0, f)
AttributeError: module 'pylab' has no attribute 'poly_between'
linear_response.py returned 256 and FAILED!

Looking for a work-around, I'll let you know if I find one.

Best,
Rob