string1 = '421'
string2 = 'aaa'
string3 = 'sina42'
string4 = 'asdasd54545454#$@$#@$@$@#'
# isalnum
print(string1.isalnum())
print(string2.isalnum())
print(string3.isalnum())
print(string4.isalnum())
# isalpha
print(string2.isalpha())
# isdecimal
print(string1.isdecimal())
# isspace
print(" ".isspace())
print(" a".isspace())
# istitle
# islower
# isupper
