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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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