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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 process_increase_expression_amount(self):
 """Looks for Positive_Regulation events with a specified Cause and a Gene_Expression theme, and processes them into INDRA statements. """

        statements = []

        pwcs = self.find_event_parent_with_event_child(
                'Positive_regulation', 'Gene_expression')
        for pair in pwcs:
            pos_reg = pair[0]
            expression = pair[1]

            cause = self.get_entity_text_for_relation(pos_reg, 'Cause')
            target = self.get_entity_text_for_relation(expression, 'Theme')

            if cause is not None and target is not None:
                theme_node = self.get_related_node(expression, 'Theme')
                assert(theme_node is not None)
                evidence = self.node_to_evidence(theme_node, is_direct=False)

                statements.append(IncreaseAmount(s2a(cause), s2a(target),
                                  evidence=evidence))
        return statements