import pandas as pd
import plotly.express as px
import datetime
data = pd.DataFrame([{
 'Start Date': datetime.datetime(2020, 1, 1),
 'End Date': datetime.datetime(2020, 2, 1),
 'Test Date': datetime.datetime(2020, 2, 1),
 'y': 100
},
 {
 'Start Date': datetime.datetime(2020, 1, 10),
 'End Date': datetime.datetime(2020, 2, 10),
 'Test Date': datetime.datetime(2020, 2, 10),
 'y': 90
}])
hover_data = {
 'Start Date': '|%x',
 'End Date': '|%x',
 'Test Date': '|%x'
}
fig = px.timeline(data, x_start="Start Date", x_end="End Date",
 y="y", text='End Date', hover_data=hover_data)
fig.show()