Write a Swift program to insert a given string to another given string where the second string will be in the middle of the first string

func insert_string(_ str1: String, _ str2: String) -> String {
    var current_index = str1.startIndex
    let char1: Character = str1[current_index]
    var result = str1
 
    while char1 == str1[current_index] {
        current_index = str1.index(after: current_index)
    }
 
    result.insert(contentsOf: str2.characters, at: current_index)
 
    return result
}
 
print(insert_string("<>", "Swift"))
print(insert_string("<>>", "Swift"))
print(insert_string("[]", "Swift"))

Output: