from matplotlib import rcParams, __version__, pyplot

print(__version__, rcParams["font.size"])
orig = dict(rcParams)
pyplot.plot([0, 1], [0, 1])
after = dict(rcParams)
for k in orig:
    if k not in after:
        print(f"missing in after: {k} = {orig[k]}")
    elif after[k] != orig[k]:
        print(f"changed after: {k} = {after[k]} != {orig[k]}")
for k in after:
    if k not in orig:
        print(f"missing in orig: {k} = {after[k]}")
print(rcParams["font.size"])
pyplot.xlabel("x")
print(rcParams["font.size"])
pyplot.show()