code: def tryAccessModifiers(self, block):
          
  
          if CFG_ACCESS_MODIFIERS < 0:
              return None
  
          if not re.match(r'^\s*((public|protected|private)\s*(slots|Q_SLOTS)?|(signals|Q_SIGNALS)\s*):\s*$', block.text()):
              return None
  
          try:
              block, notUsedColumn = self.findBracketBackward(block, 0, '{')
          except ValueError:
              return None
  
          indentation = self._blockIndent(block)
          for i in range(CFG_ACCESS_MODIFIERS):
              indentation = self._increaseIndent(indentation)
  
          dbg("tryAccessModifiers: success in line %d" % block.blockNumber())
          return indentation
docs: Check for private, protected, public, signals etc... and assume we are in a
          class definition. Try to find a previous private/protected/private... or
          class and return its indentation or null if not found.