code: def computeSmartIndent(self, block, char):
          
          try:
              foundBlock, foundColumn = self._findExpressionStart(block.previous())
          except UserWarning:
              return ''
          expression = foundBlock.text()[foundColumn:].rstrip()
          beforeExpression = foundBlock.text()[:foundColumn].strip()
  
          if beforeExpression.startswith('(module'):  # special case
              return ''
          elif beforeExpression.endswith('define'):  # special case
              return ' ' * (len(beforeExpression) - len('define') + 1)
          elif beforeExpression.endswith('let'):  # special case
              return ' ' * (len(beforeExpression) - len('let') + 1)
          else:
              return ' ' * foundColumn
docs: Compute indent for the block