GraphManager method, to get user information

getMe.swift

  public func getMe(completion: @escaping(MSGraphUser?, Error?) -> Void) {
          let meRequest = NSMutableURLRequest(url: URL(string: "\(MSGraphBaseURL)/me")!)
          let meDataTask = MSURLSessionDataTask(request: meRequest, client: self.client, completion: {
              (data: Data?, response: URLResponse?, graphError: Error?) in
              guard let meData = data, graphError == nil else {
                  completion(nil, graphError)
                  return
              }
              do {
                  // Deserialize response as a user
                  let user = try MSGraphUser(data: meData)
                  completion(user, nil)
              } catch {
                  completion(nil, error)
              }
          })
          // Execute the request
          meDataTask?.execute()
}