docs: def line_indent(self, line_nbr=None):
          """
          Returns the indent level of the specified line
  
          :param line_nbr: Number of the line to get indentation (1 base).
              Pass None to use the current line number. Note that you can also
              pass a QTextBlock instance instead of an int.
          :return: Number of spaces that makes the indentation level of the
                   current line
          """
          if line_nbr is None:
              line_nbr = self.current_line_nbr()
          elif isinstance(line_nbr, QtGui.QTextBlock):
              line_nbr = line_nbr.blockNumber()
          line = self.line_text(line_nbr)
          indentation = len(line) - len(line.lstrip())
          return indentation