for i in range(len(text)-1 ,-1 ,-1 ):
All that is doing is establishing the for loop to be for i in a range. it doesn't actually do anything to the text itself.
Your next line should do something with the text, not simply return it.
The line after that should return it. For one example:
Here we define the method itself:
Here we set an empty string for which to enter our letters:
variable1 = empty string
Here we start our loop:
for letter in text:
Here we actually do something with the letters:
variable1 = letter + variable1
Finally, we return our reversed string: