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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 _get_entries_for_calculation(self):
 """Ignores entries flagged with ignoreForCalculation"""

        mgr = self._get_provider_manager('Grading')  # what about the Proxy?
        if not mgr.supports_gradebook_column_lookup():
            raise errors.OperationFailed('Grading does not support GradebookColumn lookup')
        gradebook_id = Id(self._my_map['assignedGradebookIds'][0])
        lookup_session = mgr.get_grade_entry_lookup_session_for_gradebook(gradebook_id,
                                                                          proxy=getattr(self, "_proxy", None))
        entries = lookup_session.get_grade_entries_for_gradebook_column(self.get_gradebook_column_id())
        return [e for e in entries if not e.is_ignored_for_calculations()]