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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 init(self):
 """ To be overridden to initialize the datasets needed by the calculation """

        oq = self.oqparam
        if not oq.risk_imtls:
            if self.datastore.parent:
                oq.risk_imtls = (
                    self.datastore.parent['oqparam'].risk_imtls)
        if 'precalc' in vars(self):
            self.rlzs_assoc = self.precalc.rlzs_assoc
        elif 'csm_info' in self.datastore:
            csm_info = self.datastore['csm_info']
            if oq.hazard_calculation_id and 'gsim_logic_tree' in oq.inputs:
                # redefine the realizations by reading the weights from the
                # gsim_logic_tree_file that could be different from the parent
                csm_info.gsim_lt = logictree.GsimLogicTree(
                    oq.inputs['gsim_logic_tree'], set(csm_info.trts))
            self.rlzs_assoc = csm_info.get_rlzs_assoc()
        elif hasattr(self, 'csm'):
            self.check_floating_spinning()
            self.rlzs_assoc = self.csm.info.get_rlzs_assoc()
        else:  # build a fake; used by risk-from-file calculators
            self.datastore['csm_info'] = fake = source.CompositionInfo.fake()
            self.rlzs_assoc = fake.get_rlzs_assoc()