Animate two charts side by side got ValueError regarding frame configuration

@empet I am following the charts side by side @ the following link, and trying to animate two charts at the same time.

https://plotly.com/python/subplots/#side-by-side-subplot-lowlevel-api

My code is the following, I think I have got the data and layout part, but did not get the frame configured correctly. I got the ValueError at the end, can you let me know how to configure to assign frame to trace1 and trace2 specifically? Thanks very much for your help.

import plotly.graph_objects as go
import numpy as np

# Generate curve data
t = np.linspace(-1, 1, 100)
x = t + t ** 2
y = t - t ** 2
xm = np.min(x) - 1.5
xM = np.max(x) + 1.5
ym = np.min(y) - 1.5
yM = np.max(y) + 1.5
N = 50
s = np.linspace(-1, 1, N)
xx = s + s ** 2
yy = s - s ** 2


# Create figure
trace1 = [go.Scatter(x=x, y=y,
                     mode="lines",
                     line=dict(width=2, color="blue")),
          go.Scatter(x=x, y=y,
                     mode="lines",
                     line=dict(width=2, color="blue"))]
trace2 = [go.Scatter(x=x, y=y,
                     mode="lines",
                     line=dict(width=2, color="blue")),
          go.Scatter(x=x, y=y,
                     mode="lines",
                     line=dict(width=2, color="blue"))]

fig = go.Figure(
    data=[trace1, trace2],
    layout=go.Layout(
        xaxis=dict(range=[xm, xM], autorange=False, zeroline=False, domain=[0, 0.6]),
        yaxis=dict(range=[ym, yM], autorange=False, zeroline=False),
        xaxis2=dict(range=[xm, xM], autorange=False, zeroline=False, domain=[0.7, 1]),
        yaxis2=dict(range=[ym, yM], autorange=False, zeroline=False, anchor="x2"),
        title_text="Kinematic Generation of a Planar Curve", hovermode="closest",
        updatemenus=[dict(type="buttons",
                          buttons=[dict(label="Play", method="animate", args=[None])])]),
    frames=[
        go.Frame(
            data=[go.Scatter(
                x=[xx[k]],
                y=[yy[k]],
                mode="markers",
                marker=dict(color="red", size=10)),
                go.Scatter(
                x=[xx[k]],
                y=[yy[k]],
                mode="markers",
                marker=dict(color="red", size=10))
                ]
                )
            for k in range(N)
        ]
)
fig.show()
print('two chart is animated.')

My error message is at line 58, which is

 for k in range(N)
ValueError:
    Invalid element(s) received for the 'data' property of ...

@DennisZ

I explained how to animate simultaneously the traces in subplots in this forum thread:
https://community.plotly.com/t/multiple-lines-subplots-and-frames/28150 and gave an example in a notebook at the link displayed in my answer.