from matplotlib import pyplot as plt
from matplotlib_venn import venn3

# Drei Mengen definieren
A = set([1, 2, 3, 4, 5])
B = set([4, 5, 6, 7, 8])
C = set([2, 5, 7, 9])

venn = venn3([A, B, C], set_labels=('Menge A', 'Menge B', 'Menge C'))

# Hilfsfunktion: Menge schön als Text ausgeben
def fmt(s):
    return "\n".join(map(str, s)) if s else ""

# Labels mit tatsächlichen Elementen überschreiben
venn.get_label_by_id('100').set_text(fmt(A - B - C))          # nur A
venn.get_label_by_id('010').set_text(fmt(B - A - C))          # nur B
venn.get_label_by_id('001').set_text(fmt(C - A - B))          # nur C
venn.get_label_by_id('110').set_text(fmt(A & B - C))          # A ∩ B
venn.get_label_by_id('101').set_text(fmt(A & C - B))          # A ∩ C
venn.get_label_by_id('011').set_text(fmt(B & C - A))          # B ∩ C
venn.get_label_by_id('111').set_text(fmt(A & B & C))          # A ∩ B ∩ C

plt.title("Venn-Diagramm mit allen Elementen")
plt.show()