KeyError caused by a wrong attribute assignment within the network?

I have a dataset not well formatted as it has the following columns

Source   Target  Label_Source    Label_Target
    E   N   0.0 0.0
    A   B   1.0 1.0
    A   C   1.0 0.0
    A   D   1.0 0.0
    A   N   1.0 0.0
    S   G   0.0 0.0
    S   L   0.0 1.0
    S   C   0.0 0.0

Label_Source and Label_Target are nodes attributes Label_Source is a source's attribute while Label_Target is a target's attribute. Trying to replicate the following project: https://www.fatalerrors.org/a/python-networkx-learning-notes.html, I have encountered some errors, including a KeyError due to Label_Source. As explained in this answer: KeyError after re-running the (same) code, the problem seems caused by a wrong assignment in edge/node attributes, as the code is reading Label_Source as edge's attribute. I would like to replicate the project, as I said, so any format that could make it possible would be acceptable. However, I would really appreciate someone could explain (not only show) how to fix the issue as it is not clear to me what is driving it. What I have done so far is shown below:

import networkx as nx
from matplotlib import pyplot as plt
import pandas as pd

G = nx.from_pandas_edgelist(filtered, 'Source', 'Target',  edge_attr=True)
df_pos = nx.spring_layout(G,k = 0.3) 

nx.draw_networkx(G, df_pos)
plt.show()

node_color = [
    '#1f78b4' if G.nodes[v]["Label_Source"] == 0 # actually this assignment should just Label and it should include also Target, so the whole list of nodes and their labels. A way to address this would be to select all distinct nodes in the network and their labels
    else '#33a02c' for v in G]

# Iterate through all edges
for v, w in G.edges:
    if G.nodes[v]["Label_Source"] == G.nodes[w]["Label_Source"]: # this should refer to all the Labels 
        G.edges[v, w]["internal"] = True
    else:
        G.edges[v, w]["internal"] = False

If you could help me to understand how to fix the issue and replicate the code it would be great. I guess the error is also in trying to iterate through strings and not indices.

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