content: import React, { Component } from 'react';
  import { Collapse } from '@material-ui/core';
  
  class ListItemTransition extends Component {
      render() {
          return (
              <Collapse
                  in={this.props.in}
                  mountOnEnter={true}
                  unmountOnExit={true}>
                  {this.props.children}
              </Collapse>
  
          );
      }
  }
  
  export default ListItemTransition;