code: def base26(x, _alphabet=string.ascii_uppercase):
      
      result = []
      while x:
          x, digit = divmod(x, 26)
          if not digit:
              x -= 1
              digit = 26
          result.append(_alphabet[digit - 1])
      return ''.join(result[::-1])
docs: Return positive ``int`` ``x`` as string in bijective base26 notation.
  
      >>> [base26(i) for i in [0, 1, 2, 26, 27, 28, 702, 703, 704]]
      ['', 'A', 'B', 'Z', 'AA', 'AB', 'ZZ', 'AAA', 'AAB']
  
      >>> base26(344799)  # 19 * 26**3 + 16 * 26**2 + 1 * 26**1 + 13 * 26**0
      'SPAM'
  
      >>> base26(256)
      'IV'