input: Write a python function to compare if two strings have the same characters at the same positions.
  assert same_chars("abc", "abc") == True
  assert same_chars("abc", "abd") == False
  assert same_chars("abc", "ab") == False
  assert same_chars("hello", "hello") == True
  assert same_chars("hello", "hELLo") == False
output: def same_chars(str1, str2):
      return str1 == str2