Final answer:
The code segment that will always perform the same is the one using 'any()' function to check if any letter in 'some_string' is a numeral.
Step-by-step explanation:
The code segment that will always perform exactly the same as the one provided, regardless of the value of some_string, is:
def has_a_numeral(some_string):
found_a_numeral = any(letter in some_string for letter in '0123456789')
return found_a_numeral
This code segment uses the any() function to check if any letter in some_string is a numeral. It simplifies the code by eliminating the need for a for loop and an explicit if statement.