This is a convenience wrapper around pyplot.plot. It ensures that the
current Axes is polar (or creates one if needed) and then passes all parameters
to .pyplot.plot.
Note
When making polar plots using the pyplot API,
polar() should typically be the first command because that makes sure
a polar Axes is created. Using other commands such as plt.title()
before this can lead to the implicit creation of a rectangular Axes, in which
case a subsequent polar() call will fail.
