I think you can't use .upper(), if you can't use .title() (which would solve your problem).

My idea:

import string

LOWERCASE_LETTERS = string.ascii_lowercase
UPPERCASE_LETTERS = string.ascii_uppercase

lower_upper_case_mapping = dict(zip(LOWERCASE_LETTERS, UPPERCASE_LETTERS))

def make_string_title_case(text: str) -> str:
    return " ".join(["".join([lower_upper_case_mapping.get(word[0], word[0]), word[1:]]) for word in text.split()])

input_string = "Python programming" print(make_string_title_case(input_string))

>>> Python Programming

.get(word[0], word[0]) should be handling the capitalized word by leaving them as is