<｜begin▁of▁sentence｜>### Instruction:
In the realm of digital forensics, let's consider a hypothetical scenario where we are investigating a linear sequence of communication nodes, akin to a chain of emails or messages represented in a simplistic form. Suppose this sequence comprises of five distinct nodes, akin to participants or points of contact within a communication network, arranged in a straightforward chain-like configuration. This sequence is technically generated by the 'nx.path_graph(5)' function within the context of our investigation.

Our objective, utilizing our expertise in network analysis, is to delve into the structure of this communication chain to uncover potential pathways of information flow. We aim to execute a meticulous examination akin to a depth-first search, commencing at the initial node, identified as node 0, which represents the source or origin.

Furthermore, in recognizing the necessity of constraints in our approach to hone our focus, we impose a limit - a depth bound set at two levels from our starting point. This limit permits us to scrutinize connections emanating directly and indirectly from our source node, but only to a second-degree connection, precluding any further.

Can you assist with this specialized inquiry into the communicative sequence's structure following these precise parameters? Your guidance would be instrumental in possibly elucidating the distribution channels within the network, which could hold significance for our forensic analysis.
### Response:
import networkx as nx

# Create a path graph
G = nx.path_graph(5)

# Perform DFS in a pre-ordering starting from source node 0
preorder_nodes = list(nx.dfs_preorder_nodes(G, source=0))
print(preorder_nodes)

# Perform DFS in a pre-ordering starting from source node 0 with depth limit 2
preorder_nodes_limited = list(nx.dfs_preorder_nodes(G, source=0, depth_limit=2))
print(preorder_nodes_limited)
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