code: func (c *Client) CreatePublicToken(accessToken string) (resp CreatePublicTokenResponse, err error) {
  	if accessToken == "" {
  		return resp, errors.New("/item/public_token/create - access token must be specified")
  	}
  
  	jsonBody, err := json.Marshal(createPublicTokenRequest{
  		ClientID:    c.clientID,
  		Secret:      c.secret,
  		AccessToken: accessToken,
  	})
  
  	if err != nil {
  		return resp, err
  	}
  
  	err = c.Call("/item/public_token/create", jsonBody, &resp)
  	return resp, err
  }
docs: // CreatePublicToken generates a one-time use public token which expires in
  // 30 minutes to update an Item.
  // See https://plaid.com/docs/api/#creating-public-tokens.