content = "23"

content

'23'

isinstance(content, int)

False

type(content)

str

content.isdigit()

True

text = "one 2 three 4 five 6 seven 8 nine 10"

for x in text.split(" "):
    print(x, "==>", x.isdigit())

one ==> False
2 ==> True
three ==> False
4 ==> True
five ==> False
6 ==> True
seven ==> False
8 ==> True
nine ==> False
10 ==> True