URLSession.shared.dataTask block not running - swift

Question

I'm trying to make a request to an API. Without the completion handler, the request proceeds without issue. However, now that I've added in a completion handler, the URLSession.shared.dataTask block doesn't appear to run at all; the second print statement never prints. How should I adjust my code to fix this issue?
func makeRequestToApi(word: String, completionHandler: #escaping ([String]) -> Void) {
var array = [String]()
let appId = ""
let appKey = ""
let language = "en-us"
let unwrappedURL = URL(string: "https://od-api.oxforddictionaries.com:443/api/v2/entries/\(language)/\(word)")!
var request = URLRequest(url: unwrappedURL)
request.addValue("application/json", forHTTPHeaderField: "Accept")
request.addValue(appId, forHTTPHeaderField: "app_id")
request.addValue(appKey, forHTTPHeaderField: "app_key")
print("THIS STATEMENT PRINTS...")
let dataTask = URLSession.shared.dataTask(with: request) { (data, response, error) in
print("AND THIS STATEMENT")
if let data = data,
let _ = try? JSONSerialization.jsonObject(with: data, options: .mutableContainers) {
do {
let root = try JSONDecoder().decode(Root.self, from: data)
let results = root.results
for result in results {
for lexical in result.lexicalEntries {
for entry in lexical.entries {
for sense in entry.senses {
for example in sense.examples {
array.append(example.text)
}
}
}
}
}
} catch {
print(error)
}
completionHandler(array)
}
}
dataTask.resume()
}
This is the function that I used on another view controller that returned data for the same words:
func makeRequestToApi() {
let appId = ""
let appKey = ""
let language = "en-us"
let strictMatch = "false"
var word = search
word = word.lowercased()
let oxDicURL = URL(string: "https://od-api.oxforddictionaries.com:443/api/v2/entries/\(language)/\(word)?strictMatch=\(strictMatch)")
if let unwrappedURL = oxDicURL {
var request = URLRequest(url: unwrappedURL)
request.addValue("application/json", forHTTPHeaderField: "Accept")
request.addValue(appId, forHTTPHeaderField: "app_id")
request.addValue(appKey, forHTTPHeaderField: "app_key")
let dataTask = URLSession.shared.dataTask(with: request) { (data, response, error) in
if let data = data,
let _ = try? JSONSerialization.jsonObject(with: data, options: .mutableContainers) {
do {
let root = try JSONDecoder().decode(Root.self, from: data)
let results = root.results
for result in results {
for lexical in result.lexicalEntries {
for entry in lexical.entries {
for sense in entry.senses {
for example in sense.examples {
print(example.text)
self.array.append(example.text)
}
}
}
}
}
self.search = word
DispatchQueue.main.async() {
self.performSegue(withIdentifier: "goToDetail", sender: nil)
}
} catch {
print(error)
}
}
}
dataTask.resume()
}
}