import re

text1 = "admin@kbtu.kz"
text2 = "@kbtu.kz"
pattern = r"[a-z]+@[a-z]+\.[a-z]{2}"

res1 = re.match(pattern,text1)
res2 = re.match(pattern,text2)

print(res1)
print(res2)

2ee687b3f95cd87b50964ad60a2a13532eabefa8
<mask token>

<mask token>
print(res1)
print(res2)

<mask token>
text1 = 'admin@kbtu.kz'
text2 = '@kbtu.kz'
pattern = '[a-z]+@[a-z]+\\.[a-z]{2}'
res1 = re.match(pattern, text1)
res2 = re.match(pattern, text2)
print(res1)
print(res2)

import re
text1 = 'admin@kbtu.kz'
text2 = '@kbtu.kz'
pattern = '[a-z]+@[a-z]+\\.[a-z]{2}'
res1 = re.match(pattern, text1)
res2 = re.match(pattern, text2)
print(res1)
print(res2)

import re

text1 = "admin@kbtu.kz"
text2 = "@kbtu.kz"
pattern = r"[a-z]+@[a-z]+\.[a-z]{2}"

res1 = re.match(pattern,text1)
res2 = re.match(pattern,text2)

print(res1)
print(res2)
