Returns all flow objects.

def ReadAllFlowObjects(
      self,
      client_id = None,
      min_create_time = None,
      max_create_time = None,
      include_child_flows = True,
  ):
    """Returns all flow objects."""
    res = []
    for flow in itervalues(self.flows):
      if ((client_id is None or flow.client_id == client_id) and
          (min_create_time is None or flow.create_time >= min_create_time) and
          (max_create_time is None or flow.create_time <= max_create_time) and
          (include_child_flows or not flow.parent_flow_id)):
        res.append(flow.Copy())
    return res