code: def _maxflow(graph, source, target, capacity=None):
      """Returns a maximum flow between the given source and target vertices
      in a graph.
  
      A maximum flow from I{source} to I{target} is an assignment of
      non-negative real numbers to the edges of the graph, satisfying
      two properties:
  
          1. For each edge, the flow (i.e. the assigned number) is not
             more than the capacity of the edge (see the I{capacity}
             argument)
  
          2. For every vertex except the source and the target, the
             incoming flow is the same as the outgoing flow.
  
      The value of the flow is the incoming flow of the target or the
      outgoing flow of the source (which are equal). The maximum flow
      is the maximum possible such value.
  
      @param capacity: the edge capacities (weights). If C{None}, all
        edges have equal weight. May also be an attribute name.
      @return: a L{Flow} object describing the maximum flow
      """
      return Flow(
          graph, *GraphBase.maxflow(graph, source, target, capacity)
      )
  
imports: from igraph._igraph import GraphBase
  from igraph.clustering import VertexClustering
label_desc: Use image node_id 4 for calling a global function with example usage: _maxflow(graph, source, target, capacity) and returns: Flow