title: How do I display a timedelta in the format HH:MM:SS on my Plotly Express line chart's axis?
body: <p>I want to plot a continuous 'Time' column against dates on a simple timeseries linechart in plotly express. The 'Time' column starts out as a string, in the format HH:MM:SS, but when I plot this outright it is treated as discrete values. To remedy this and make it continuous I tried converting to timedelta data type, using <code>pd.to_timedelta</code>. This correctly converts my column into nanoseconds and the shape of the line and axis looks correct. However I do not want to display the axis as nanoseconds, or any other fixed unit, I would like it to display as HH:MM:SS, but am unsure how I might format this.</p>
  <p><a href="https://i.stack.imgur.com/NS88n.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NS88n.png" alt="Plotly chart with Time Delta on Y axis" /></a></p>