<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def grayify_cmap(cmap):
 """Return a grayscale version of the colormap. `Source`__ __ https://jakevdp.github.io/blog/2014/10/16/how-bad-is-your-colormap/ """

    cmap = plt.cm.get_cmap(cmap)
    colors = cmap(np.arange(cmap.N))
    # convert RGBA to perceived greyscale luminance
    # cf. http://alienryderflex.com/hsp.html
    RGB_weight = [0.299, 0.587, 0.114]
    luminance = np.sqrt(np.dot(colors[:, :3] ** 2, RGB_weight))
    colors[:, :3] = luminance[:, np.newaxis]
    return mplcolors.LinearSegmentedColormap.from_list(cmap.name + "_grayscale", colors, cmap.N)