How to modify the font size in matplotlib-venn

If out is the object returned by venn3(), the text objects are just stored as out.set_labels and out.subset_labels, so you can do:

from matplotlib import pyplot as plt
from matplotlib_venn import venn3, venn3_circles
set1 = set(['A', 'B', 'C', 'D'])
set2 = set(['B', 'C', 'D', 'E'])
set3 = set(['C', 'D',' E', 'F', 'G'])

out = venn3([set1, set2, set3], ('Set1', 'Set2', 'Set3'))
for text in out.set_labels:
    text.set_fontsize(14)
for text in out.subset_labels:
    text.set_fontsize(16)

In my case some values of the out.subset_labels were NoneType. To omit that problem I did:

from matplotlib import pyplot as plt
from matplotlib_venn import venn3, venn3_circles
set1 = set(['A', 'B', 'C', 'D'])
set2 = set(['B', 'C', 'D', 'E'])
set3 = set(['C', 'D',' E', 'F', 'G'])

out = venn3([set1, set2, set3], ('Set1', 'Set2', 'Set3'))
for text in out.set_labels:
    text.set_fontsize(15)
for x in range(len(out.subset_labels)):
    if out.subset_labels[x] is not None:
        out.subset_labels[x].set_fontsize(15)