<｜begin▁of▁sentence｜>### Instruction:
In reviewing the sustainability report for the construction project's resource allocation network, we've modeled the flow of resources as a directed graph with weighted edges corresponding to the cost or benefit of transfer. The graph is stored in a 'project-resource-flow.gml' file. Each connection between nodes (representing project stages or resource points) is detailed as a set, with the figures capturing the origin, destination, and net environmental impact value of transporting resources.

The edge set provided includes the following interactions:
- From the initial planning phase (0) to the procurement stage (1), with an impact value of +2.
- From the procurement stage (1) to the construction phase (2), showing a negative impact value of -5.
- From the construction phase (2) to the finishing touches (3), with a positive impact of +1.
- And back from the finishing touches (3) to the initial planning phase (0), closing the loop with an impact value of +1.

Given the imperative to minimize environmental burdens in our project cycle, I need to confirm whether the graph indicating the passage of resources includes a cycle that overall reduces environmental performance (i.e., contains a cycle with a net negative impact). Could you verify if our 'project-resource-flow.gml' data depicts such a negative edge cycle within our network?
### Response:
import networkx as nx

# Create a directed graph
G = nx.DiGraph()

# Add edges with weights
G.add_weighted_edges_from([(0, 1, 2), (1, 2, -5), (2, 3, 1), (3, 0, 1)])

# Check for the existence of a negative edge cycle
has_negative_cycle = nx.negative_edge_cycle(G, weight='weight')

print(f'Graph has a negative edge cycle: {has_negative_cycle}')
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