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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 decrypt_pillar(self, pillar):
        '''
        Decrypt the specified pillar dictionary items, if configured to do so
        '''
        errors = []
        if self.opts.get('decrypt_pillar'):
            decrypt_pillar = self.opts['decrypt_pillar']
            if not isinstance(decrypt_pillar, dict):
                decrypt_pillar = \
                    salt.utils.data.repack_dictlist(self.opts['decrypt_pillar'])
            if not decrypt_pillar:
                errors.append('decrypt_pillar config option is malformed')
            for key, rend in six.iteritems(decrypt_pillar):
                ptr = salt.utils.data.traverse_dict(
                    pillar,
                    key,
                    default=None,
                    delimiter=self.opts['decrypt_pillar_delimiter'])
                if ptr is None:
                    log.debug('Pillar key %s not present', key)
                    continue
                try:
                    hash(ptr)
                    immutable = True
                except TypeError:
                    immutable = False
                try:
                    ret = salt.utils.crypt.decrypt(
                        ptr,
                        rend or self.opts['decrypt_pillar_default'],
                        renderers=self.rend,
                        opts=self.opts,
                        valid_rend=self.opts['decrypt_pillar_renderers'])
                    if immutable:
                        # Since the key pointed to an immutable type, we need
                        # to replace it in the pillar dict. First we will find
                        # the parent, and then we will replace the child key
                        # with the return data from the renderer.
                        parent, _, child = key.rpartition(
                            self.opts['decrypt_pillar_delimiter'])
                        if not parent:
                            # key is a top-level key, so the pointer to the
                            # parent is the pillar dict itself.
                            ptr = pillar
                        else:
                            ptr = salt.utils.data.traverse_dict(
                                pillar,
                                parent,
                                default=None,
                                delimiter=self.opts['decrypt_pillar_delimiter'])
                        if ptr is not None:
                            ptr[child] = ret
                except Exception as exc:
                    msg = 'Failed to decrypt pillar key \'{0}\': {1}'.format(
                        key, exc
                    )
                    errors.append(msg)
                    log.error(msg, exc_info=True)
        return errors