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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_collection(self, collection_name):
 """ Get PyMongo client pointing to the current DB and the given collection. :return: MongoDB client of the current database and given collection. :raise DataSourceError """

        try:
            return self._database[collection_name]
        except InvalidName as ex:
            raise DataSourceError("Cannot access MongoDB collection %s!"
                                  % collection_name) from ex
        except Exception as ex:
            raise DataSourceError("Unexpected error when accessing MongoDB"
                                  "collection %s!"
                                  % collection_name) from ex