<｜begin▁of▁sentence｜>### Instruction:
As a cartographer, you've been tasked with creating a navigational map for a transportation network. To effectively design the map, you need to calculate the average in-degree of the network. Utilizing the RunningMean.add() function from the networkx API will allow you to efficiently obtain this key metric, ensuring accurate representation of the network's connectivity on the map.
### Response:
import networkx as nx

# Suppose we want to calculate the average in-degree of a graph
# First, create a directed graph
G = nx.DiGraph()
G.add_edges_from([(1, 2), (1, 3), (2, 3), (3, 4), (4, 2)])

# Calculate in-degrees
in_degrees = G.in_degree()

# Initialize running mean object
from RunningMean import RunningMean
rm = RunningMean()

# Add in-degree of each node to the running mean
for _, degree in in_degrees:
    rm.add(degree)

# Get the current running mean
average_in_degree = rm.mean
print('Average in-degree:', average_in_degree)
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