view and then close the figure automatically in matplotlib?

Documentation on pyplot.show() reads:

matplotlib.pyplot.show(*args, **kw)

Display a figure. When running in ipython with its pylab mode, display
all figures and return to the ipython prompt.

In non-interactive mode, display all figures and block until the figures have been closed; in interactive mode it has no effect
unless figures were created prior to a change from non-interactive to
interactive mode (not recommended). In that case it displays the
figures but does not block.

A single experimental keyword argument, block, may be set to True or False to override the blocking behavior described above.

So the solution is this:

plt.show(block=False)
plt.pause(3)
plt.close()