php is flexible and loosely-typed. What does this mean. Give example

<?php
class Salesperson
{
  private $special_boss_requests=array();
  
  public function add_boss_requests($request)
  {
    //add the request to the list of things to do
    $this->special_boss_requests[]=$request;
  }
  
  function sale($item,$credit_card,$buyer)
  {
    $this->scan_item($item);
    $receipt = $this->swipe_credit_card($credit_card);
    $this->give_receipt_and_item($receipt, $item, $buyer);
    //now perform all the boss's special requests, passing the buyer's name to each one
    foreach($this->special_boss_requests as $request){
      call_user_func($request,$buyer);
    } 
  }

  function scan_item($item)
  {
    // scan the item
  }

  function swipe_credit_card($card)
  {
    // send credit card data and get a receipt back
    return "receipt";
  }

  function give_receipt_and_item($receipt, $item, $buyer)
  {
    // give the stuff to the person who is buying the item
  }
}

//start your day
$me=new Salesperson();
//you sell a pari of shoes to joe smith
$me->sale("shoes","joe smith credit card","Joe Smith");
//at this point you are not saying thank you yet
//the boss comes up with idea to say thank you which is our lambda function
$say_thank_you=create_function('$name','print "Thank you,{$name} for shopping with us!";');
//the boss tells you to do it
$me->add_boss_requests($say_thank_you);
//now when you perform a sale...
//sell coffee to mary smith
$me->sale("coffee", "mary smith credit card", "mary smith");
//after doing everying you say, thank you mary smith for shopping with us
//now the boss comes up with another idea-make sure you also tell them about our website
//the boss comes up with idea to say thank you which is our lambda function
$say_website_reminder=create_function('$name','print "Also{$name}, make sure you visit our website";');
//the obss tells you to do it
$me->add_boss_requests($say_website_reminder);
//at this point you now have $say_thank_you and say_website_reminder
$another_reminder=create_function('$name', 'print "and {$name}, also close the door on the way out";');
$me->add_boss_requests($another_reminder);
//sell a car to george smith
$me->sale("car", "george smith credit card","george smith");
//now george smith should hear both at the end

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To be honest, I RARELY ever use anonymous methods / lambda functions. PHP is generally so flexible and loosely-typed that the predefined functions can often do what you need and they perform better.