This avoids a deprecation warning from matplotlib:
tfomics/impress.py:47: MatplotlibDeprecationWarning: Passing non-integers as three-element
position specification is deprecated since 3.3 and will be removed two minor releases later.
ax = fig.add_subplot(num_rows,num_cols,n+1)
This avoids a deprecation warning from matplotlib:
this is using matplotlib version 3.3.4