<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def requires_list(self):
 """ It is important that this property is calculated lazily. Getting the 'requires' attribute may trigger a package load, which may be avoided if this variant is reduced away before that happens. """

        requires = self.variant.get_requires(build_requires=self.building)
        reqlist = RequirementList(requires)

        if reqlist.conflict:
            raise ResolveError(
                "The package %s has an internal requirements conflict: %s"
                % (str(self), str(reqlist)))

        return reqlist