<｜begin▁of▁sentence｜>### Instruction:
Suppose you have a tree graph where each non-leaf node has 2 children and there are 3 levels in total. Using Plotly, how would you compute and display the edge labels positions of this tree graph ensuring that the labels do not overlap with the edges themselves?
### Response:
import plotly.graph_objs as go
from igraph import *

# Function to calculate the label position of an edge
class CustomPlotlyEdgeDrawer(PlotlyEdgeDrawer):
    def get_label_position(self, edge):
        # Custom logic to determine label position
        # For example, we use the midpoint here
        src = self.coords[edge.source]
        tgt = self.coords[edge.target]
        midpoint = ((src[0] + tgt[0]) / 2, (src[1] + tgt[1]) / 2)
        alignment = 'center'
        return midpoint, alignment

# Assuming we have a graph setup
g = Graph.Tree(3, 2)  # Example for a simple tree graph
layout = g.layout('kk')
custom_drawer = CustomPlotlyEdgeDrawer(g, layout)

# Get label position for the first edge
label_pos, alignment = custom_drawer.get_label_position(g.es[0])
print(f'Label Position: {label_pos}, Alignment: {alignment}')

# Create a plotly trace for the edge with label
edge_trace = go.Scatter(
    x=[label_pos[0]], y=[label_pos[1]],
    text=[g.es[0]['label'] if 'label' in g.es[0].attributes() else ''],
    mode='text',
    textposition=alignment
)

# Plot using Plotly (not shown as it requires rendering in a browser or Jupyter notebook)
<|EOT|>
