Retrieve data from array in another function

I am trying to retrieve the data set in an array in one function, in a different function. I appended the data i want into the OtherUserArray in the createNewConversation function. However when i try the retrieve this data in the sendMessage function, it prints an empty array.

import MessageKit
import InputBarAccessoryView
import FirebaseAuth
import Firebase
import Foundation


final class DatabaseManager {

static let shared = DatabaseManager()

var foundOtherUser:String?

var OtherUserArray = [String]()

}

extension DatabaseManager {

// create a new conversation with target user, uid and first sent message
public func createNewConversation(with otherUserUid: String, name: String, firstMessage: Message, completion: @escaping(Bool) -> Void) {
    
    let db = Firestore.firestore()
    let CurrentUser = Auth.auth().currentUser?.uid
    let defaults = UserDefaults.standard
    defaults.set(CurrentUser, forKey: "uid")
    
    guard let currentUid = UserDefaults.standard.string(forKey: "uid"), let currentName = UserDefaults.standard.string(forKey: "usersFullname") else {
        return
    }
   
    let messageDate = firstMessage.sentDate
    
    let dateString = MessageViewController.dateFormatter.string(from: messageDate)
    
    var message = ""
    
    let conversationId = firstMessage.messageId
    
    let newConversationData: [String:Any] = [
    "id": conversationId,
    "other_user-uid": otherUserUid,
        "name": name,
    "latest-message": [
        "date": dateString,
        "message": message,
        "is-read": false
      ]
    ]
    
    // save other user uid to global var
    
    OtherUserArray.append(otherUserUid)

    }
}
}

 public func sendMessage(to conversation: String, name: String, newMessage: Message, completion: @escaping(Bool) -> Void) {
    
    // update the latest message
    print(self.OtherUserArray)

}