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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 render_pillar(self, matches, errors=None):
        '''
        Extract the sls pillar files from the matches and render them into the
        pillar
        '''
        pillar = copy.copy(self.pillar_override)
        if errors is None:
            errors = []
        for saltenv, pstates in six.iteritems(matches):
            pstatefiles = []
            mods = set()
            for sls_match in pstates:
                matched_pstates = []
                try:
                    matched_pstates = fnmatch.filter(self.avail[saltenv], sls_match)
                except KeyError:
                    errors.extend(
                        ['No matching pillar environment for environment '
                         '\'{0}\' found'.format(saltenv)]
                    )
                if matched_pstates:
                    pstatefiles.extend(matched_pstates)
                else:
                    pstatefiles.append(sls_match)

            for sls in pstatefiles:
                pstate, mods, err = self.render_pstate(sls, saltenv, mods)

                if err:
                    errors += err

                if pstate is not None:
                    if not isinstance(pstate, dict):
                        log.error(
                            'The rendered pillar sls file, \'%s\' state did '
                            'not return the expected data format. This is '
                            'a sign of a malformed pillar sls file. Returned '
                            'errors: %s',
                            sls,
                            ', '.join(["'{0}'".format(e) for e in errors])
                        )
                        continue
                    pillar = merge(
                        pillar,
                        pstate,
                        self.merge_strategy,
                        self.opts.get('renderer', 'yaml'),
                        self.opts.get('pillar_merge_lists', False))

        return pillar, errors