show matplotlib colormaps
import matplotlib as mpl
import matplotlib.pyplot as plt
def plot_colorMaps(cmap):
    fig, ax = plt.subplots(figsize=(4,0.4))
    col_map = plt.get_cmap(cmap)
    mpl.colorbar.ColorbarBase(ax, cmap=col_map, orientation = 'horizontal')
    plt.show()
for cmap_id in plt.colormaps():
    print(cmap_id)
    plot_colorMaps(cmap_id)
