<｜begin▁of▁sentence｜>### Instruction:
As an art therapist, you are working on a project to visualize a tree diagram representing the relationships between 5 individuals in a family. Each individual is represented as a vertex in the graph, and you would like to collect and print custom labels for each vertex, reflecting the individual's personal thoughts and feelings. You have a custom attribute collector defined using the AttributeCollectorMeta metaclass, with a default vertex_label set to an empty string. You need to implement the collection and printing of these labels for each vertex when using the networkx library to plot the tree graph with a branching factor of 2.
### Response:
from igraph import Graph

# Define a custom attribute collector with default values

# The metaclass allows us to define default values for attributes
# and how they should be collected during graph plotting
class MyAttributeCollector(metaclass=AttributeCollectorMeta):
    # Set the default value for the vertex_label attribute
    vertex_label = ('', str)
    # Prefix for keyword arguments passed to __plot__ to recognize the attributes
    _kwds_prefix = 'vertex_'

# Now we create a graph and use the attribute collector to plot it
g = Graph.Tree(5, 2)

# Assume we have a function that plots the graph using the attribute collector
def plot_graph(graph, attr_collector):
    # For demonstration purposes, just print the vertex labels
    for v in graph.vs:
        label = attr_collector.collect_attributes(v.index)['vertex_label']
        print(f'Vertex {v.index} label: {label}')

# Plotting the graph
plot_graph(g, MyAttributeCollector())
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