Sets optional arguments for the spectrogram appearance.

        Available options:

        :param nfft: size of FFT window to use
        :type nfft: int
        :param overlap: percent overlap of window
        :type overlap: number
        :param window: Type of window to use, choices are hanning, hamming, blackman, bartlett or none (rectangular)
        :type window: string
        :param colormap: Gets set by colormap editor. Holds the information to generate the colormap. Items: :meth:`lut<pyqtgraph:pyqtgraph.ImageItem.setLookupTable>`, :meth:`levels<pyqtgraph:pyqtgraph.ImageItem.setLevels>`, state (info for editor)
        :type colormap: dict

def setSpecArgs(**kwargs):
        """Sets optional arguments for the spectrogram appearance.

        Available options:

        :param nfft: size of FFT window to use
        :type nfft: int
        :param overlap: percent overlap of window
        :type overlap: number
        :param window: Type of window to use, choices are hanning, hamming, blackman, bartlett or none (rectangular)
        :type window: string
        :param colormap: Gets set by colormap editor. Holds the information to generate the colormap. Items: :meth:`lut<pyqtgraph:pyqtgraph.ImageItem.setLookupTable>`, :meth:`levels<pyqtgraph:pyqtgraph.ImageItem.setLevels>`, state (info for editor)
        :type colormap: dict
        """
        for key, value in kwargs.items():
            if key == 'colormap':
                SpecWidget.imgArgs['lut'] = value['lut']
                SpecWidget.imgArgs['levels'] = value['levels']
                SpecWidget.imgArgs['state'] = value['state']
                for w in SpecWidget.instances:
                    w.updateColormap()
            else:
                SpecWidget.specgramArgs[key] = value