matplotlib.axis.XAxis.axis_date
- 
XAxis.axis_date(tz=None) - 
Sets up x-axis ticks and labels that treat the x data as dates. tz is a
tzinfoinstance or a timezone string. This timezone is used to create date labels. 
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    https://matplotlib.org/3.0.0/api/_as_gen/matplotlib.axis.XAxis.axis_date.html