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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 schedule(self, materials=None, variables=None, secure_variables=None):
 """ Scheduling allows user to trigger a specific pipeline. :param materials: material revisions to use. :param variables: environment variables to set. :param secure_variables: secure environment variables to set. :return: a text confirmation. """

        return self._pipeline.schedule(
            name=self.data.name,
            materials=materials,
            variables=variables,
            secure_variables=secure_variables
        )