utils.delta_time function returns KeyError

[RahulJois]

import fastf1 as ff1
from fastf1 import plotting
from matplotlib import pyplot as plt
from fastf1 import utils

plotting.setup_mpl()
quali = ff1.get_session(2021, 'Bahrain', 'Q')
laps = quali.load_laps()
lec = laps.pick_driver('LEC').pick_fastest()
ham = laps.pick_driver('HAM').pick_fastest()

delta_time, ref_tel, compare_tel = utils.delta_time(ham, lec)

fig, ax = plt.subplots()

ax.plot(ref_tel['Distance'], ref_tel['Speed'],
color=plotting.TEAM_COLORS[ham['Team']])
ax.plot(compare_tel['Distance'], compare_tel['Speed'],
color=plotting.TEAM_COLORS[lec['Team']])

When executed returns this

core INFO Loading Bahrain Grand Prix - Qualifying
api INFO No cached data found. Downloading...
api INFO Fetching timing data...
api INFO Parsing timing data...
api INFO Data has been written to cache!
api INFO No cached data found. Downloading...
api INFO Fetching timing app data...
api INFO Data has been written to cache!
core INFO Processing timing data...
api INFO No cached data found. Downloading...
api INFO Fetching session status data...
api INFO Data has been written to cache!
api INFO No cached data found. Downloading...
api INFO Fetching track status data...
api INFO Data has been written to cache!
core INFO Loaded data for 20 drivers: ['33', '44', '10', '77', '11', '55', '7', '31', '18', '3', '16', '99', '22', '5', '14', '4', '63', '47', '9', '6']
Traceback (most recent call last):
File "/Users/rahul/testing.py", line 15, in
delta_time, ref_tel, compare_tel = utils.delta_time(ham, lec)
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/fastf1/utils.py", line 68, in delta_time
ref = reference_lap.get_car_data(interpolate_edges=True).add_distance()
File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/fastf1/core.py", line 1810, in get_car_data
car_data = self.session.car_data[self['DriverNumber']].slice_by_lap(self, **kwargs).reset_index(drop=True)
KeyError: '44'

[theOehrly]

You haven't loaded any car telemetry data. You need a recording of the live telemetry from the session for that. The example was not yet updated to show that. I have just updated it.

[RahulJois]

So, I won't be able to plot unless I have the live timing data ? Is there a way to download the live timing data after the session is over ?

[theOehrly]

Last season it was possible to download this data after a session. But it is no longer possible this season sadly.

[FMPete]

Could we together make sure that the data is downloaded live and then use it together? Or rather how would this be done in the easiest poossible way? I could happily pay a minor sum if needed to host something etc. As this data is available live, I still don't see any problems with F1-app or FOM interest.

[theOehrly]

Could we together make sure that the data is downloaded live and then use it together? Or rather how would this be done in the easiest poossible way? I could happily pay a minor sum if needed to host something etc. As this data is available live, I still don't see any problems with F1-app or FOM interest.

We "could" but this will not happen within the scope of this project and I won't do it. For legal reasons.