<｜begin▁of▁sentence｜>### Instruction:
As an Emergency Medical Dispatcher, you receive a call reporting a medical emergency at a busy intersection. After prioritizing the call, you dispatch medical personnel and resources accordingly. The caller is instructed on what to do to assist until help arrives. Now, in this scenario, we need to calculate the maximum flow of ambulances and personnel from a hospital to the location of this emergency. Using the Python library igraph, you should be able to obtain the string representation of the flow object using the __repr__ method of the Flow class.
### Response:
from igraph import Graph

# Let's first create a directed graph with some edges
adjacency_matrix = [[0, 1, 0, 0],
                   [0, 0, 1, 0],
                   [0, 0, 0, 1],
                   [0, 0, 0, 0]]
g = Graph.Adjacency(adjacency_matrix, mode='DIRECTED')

# Now we calculate the max flow between vertex 0 and 3
flow = g.maxflow(0, 3)

# Get the string representation of the flow object
flow_str = flow.__repr__()
print(flow_str)
<|EOT|>
