def _dfs(graph, visited, count, node):
visited[node] = count<EOL>for each in graph[node]:<EOL><INDENT>if (each not in visited):<EOL><INDENT>_dfs(graph, visited, count, each)<EOL><DEDENT><DEDENT>
Depth-first search subfunction adapted for accessibility algorithms.

@type  graph: graph, digraph, hypergraph
@param graph: Graph.

@type  visited: dictionary
@param visited: List of nodes (visited nodes are marked non-zero).

@type  count: number
@param count: Counter of connected components.

@type  node: node
@param node: Node to be explored by DFS.