You are reading an old version of the documentation (v2.2.2). For the latest version see https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.convert_xunits.html
Version 2.2.2
matplotlib
Fork me on GitHub

matplotlib.axes.Axes.convert_xunits

Axes.convert_xunits(x)

For artists in an axes, if the xaxis has units support, convert x using xaxis unit type