code: def parse_balanced_image(self, markup):
          
          
  
          opened = 0
          closed = 0
          for i in range(len(markup)):
              if markup[i] == "[": opened += 1
              if markup[i] == "]": closed += 1
              if opened == closed:
                  return markup[:i+1]
                  
          return markup
docs: Corrects Wikipedia image markup.
  
          Images have a description inside their link markup that 
          can contain link markup itself, make sure the outer "[" and "]" brackets 
          delimiting the image are balanced correctly (e.g. no [[ ]] ]]).
  
          Called from parse_images().