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Python - Reverse a string without using built in functions to manipulate string

Just for fun. Reversing a string in the non pythonic way.
class MakeBackwardString:

def __init__(self, mystring):
self.mystring = mystring

def reverse(self) -> str: # reverse using loop
BACKWARD_STRING = "" # b will hold the reversed string
if isinstance(self.mystring, str): # checks if input is string
for i in reversed(range(0, len(self.mystring))): # iterates through the string
BACKWARD_STRING += self.mystring[i] # concats letters to b in reverse order
return BACKWARD_STRING # returns result

def reverse_capitalize(self) -> str:
return self.reverse().capitalize()

def reverse_title(self) -> str:
return self.reverse().title()

def reverse_lower(self) -> str:
return self.reverse().lower()

def reverse_upper(self) -> str:
return self.reverse().upper()

def reverse_using_list(self) -> str: # reverse using list
return ''.join(list(self.mystring)[::-1])

obj = MakeBackwardString("This is a string")
print(obj.reverse())
print(obj.reverse_capitalize())
print(obj.reverse_title())
print(obj.reverse_lower())
print(obj.reverse_upper())
print(obj.reverse_using_list())
Output
gnirts a si sihT
Gnirts a si siht
Gnirts A Si Siht
gnirts a si siht
GNIRTS A SI SIHT
gnirts a si sihT

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