How to use the netlify-cms-ui-default.lengths.pageMargin function in netlify-cms-ui-default

import React from 'react';
import PropTypes from 'prop-types';
import ImmutablePropTypes from 'react-immutable-proptypes';
import styled from '@emotion/styled';
import { connect } from 'react-redux';
import { lengths } from 'netlify-cms-ui-default';
import { getNewEntryUrl } from 'Lib/urlHelper';
import Sidebar from './Sidebar';
import CollectionTop from './CollectionTop';
import EntriesCollection from './Entries/EntriesCollection';
import EntriesSearch from './Entries/EntriesSearch';
import { VIEW_STYLE_LIST } from 'Constants/collectionViews';

const CollectionContainer = styled.div`
  margin: ${lengths.pageMargin};
`;

const CollectionMain = styled.main`
  padding-left: 280px;
`;

class Collection extends React.Component {
  static propTypes = {
    searchTerm: PropTypes.string,
    collectionName: PropTypes.string,
    isSearchResults: PropTypes.bool,
    collection: ImmutablePropTypes.map.isRequired,
    collections: ImmutablePropTypes.orderedMap.isRequired,
  };

  state = {

components,
  shadows,
} from 'netlify-cms-ui-default';
import { createNewEntry } from 'Actions/collections';
import {
  loadUnpublishedEntries,
  updateUnpublishedEntryStatus,
  publishUnpublishedEntry,
  deleteUnpublishedEntry,
} from 'Actions/editorialWorkflow';
import { selectUnpublishedEntriesByStatus } from 'Reducers';
import { EDITORIAL_WORKFLOW, status } from 'Constants/publishModes';
import WorkflowList from './WorkflowList';

const WorkflowContainer = styled.div`
  padding: ${lengths.pageMargin} 0;
  height: 100vh;
`;

const WorkflowTop = styled.div`
  ${components.cardTop};
`;

const WorkflowTopRow = styled.div`
  display: flex;
  justify-content: space-between;

  span[role='button'] {
    ${shadows.dropDeep};
  }
`;

import React from 'react';
import styled from '@emotion/styled';
import { translate } from 'react-polyglot';
import { lengths } from 'netlify-cms-ui-default';
import PropTypes from 'prop-types';

const NotFoundContainer = styled.div`
  margin: ${lengths.pageMargin};
`;

const NotFoundPage = ({ t }) => (
  
    <h2>{t('app.notFoundPage.header')}</h2>
  
);

NotFoundPage.propTypes = {
  t: PropTypes.func.isRequired,
};

export default translate()(NotFoundPage);