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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def mark_targets_as_explicit (self, target_names):
 """Add 'target' to the list of targets in this project that should be build only by explicit request."""


        # Record the name of the target, not instance, since this
        # rule is called before main target instaces are created.
        assert is_iterable_typed(target_names, basestring)
        self.explicit_targets_.update(target_names)