def keywords2marc(self, key, values):
    """Populate the ``695`` MARC field.

    Also populates the ``084`` and ``6531`` MARC fields through side effects.
    """
    result_695 = self.get('695', [])
    result_084 = self.get('084', [])
    result_6531 = self.get('6531', [])

    for value in values:
        schema = value.get('schema')
        source = value.get('source')
        keyword = value.get('value')

        if schema == 'PACS' or schema == 'PDG':
            result_084.append({
                '2': schema,
                '9': source,
                'a': keyword,
            })
        elif schema == 'JACOW':
            result_6531.append({
                '2': 'JACoW',
                '9': source,
                'a': keyword,
            })
        elif schema == 'INSPIRE':
            result_695.append({
                '2': 'INSPIRE',
                '9': source,
                'a': keyword,
            })
        elif schema == 'INIS':
            result_695.append({
                '2': 'INIS',
                '9': source,
                'a': keyword,
            })
        elif source != 'magpie':
            result_6531.append({
                '9': source,
                'a': keyword,
            })

    self['6531'] = result_6531
    self['084'] = result_084
    return result_695
Populate the ``695`` MARC field.

    Also populates the ``084`` and ``6531`` MARC fields through side effects.