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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 _init_formats(self):
 """ Initialise default formats. """

        theme = self._color_scheme
        # normal message format
        fmt = QtGui.QTextCharFormat()
        fmt.setForeground(theme.foreground)
        fmt.setBackground(theme.background)
        self._formats[OutputFormat.NormalMessageFormat] = fmt

        # error message
        fmt = QtGui.QTextCharFormat()
        fmt.setForeground(theme.error)
        fmt.setBackground(theme.background)
        self._formats[OutputFormat.ErrorMessageFormat] = fmt

        # debug message
        fmt = QtGui.QTextCharFormat()
        fmt.setForeground(theme.custom)
        fmt.setBackground(theme.background)
        self._formats[OutputFormat.CustomFormat] = fmt