<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _construct(self, targets, control_flow_slice=False):
 """ 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. """


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

        else:
            self._construct_default(targets)