'Construct a dependency graph based on given parameters.
:param targets:             A list of tuples like (CFGNode, statement ID)
:param control_flow_slice:  Is the backward slicing only depends on CFG or not.'

def _construct(self, targets, control_flow_slice=False):

    if control_flow_slice:
        simruns = [r for (r, _) in targets]
        self._construct_control_flow_slice(simruns)
    else:
        self._construct_default(targets)
