I have a problem with a switch statement. Can someone please HELP!

var europeanCapitals: [String] = []
var asianCapitals: [String] = []
var otherCapitals: [String] = []

let world = [
  "BEL": "Brussels", 
  "LIE": "Vaduz", 
  "BGR": "Sofia", 
  "USA": "Washington D.C.", 
  "MEX": "Mexico City", 
  "BRA": "Brasilia", 
  "IND": "New Delhi", 
  "VNM": "Hanoi"]

for (key, value) in world {
    // Enter your code below
    switch world {
    case "BEL": europeanCapitals.append("Brussels")
    case "LIE": europeanCapitals.append("Vaduz")
    case "BGR": europeanCapitals.append("Sofia")
    case "USA": otherCapitals.append("Washington D.C.")
    case "MEX": otherCapitals.append("Mexico City")
    case "BRA": otherCapitals.append("Brasilia")
    case "IND": asianCapitals.append("New Delhi")
    case "VNM": asianCapitals.append("Hanoi")
    }
    // End code
}