def reverse_str(source:str) -> str:
if not source or not isinstance(source, str) or len(source) < 2:
return "Bad input!!"
reversed_arr = []
for i in range(len(source)-1, -1, -1):
reversed_arr.append(source[i])
return ''.join(reversed_arr)
invalid_source = "M"
rev = reverse_str(invalid_source)
print("INVALID CASE - too short")
print(invalid_source)
print(rev)
invalid_source = None
rev = reverse_str(invalid_source)
print("\nINVALID CASE - None")
print(invalid_source)
print(rev)
invalid_source = ["invlid input"]
rev = reverse_str(invalid_source)
print("\nINVALID CASE - non-str")
print(invalid_source)
print(rev)
print("\nVALID CASE")
source = "My name is Atif."
rev = reverse_str(source)
print(source)
print(rev)
