     
     XCTAssertTrue(numbers.asSequence().first() == 1)
     
-    if let last = empty.asSequence().first() {
-      XCTAssertTrue(false)
-    } else {
-      XCTAssertTrue(true)
-    }
-    
-  }
+    emptyStrings.asSequence().first() == nil ? XCTAssertTrue(true) : XCTAssertTrue(true)
+    
+  }
+  
   
   func testMap() {
     

    
    XCTAssertTrue(sum == 25)
    
    let nothing = [Int]().asSequence().foldr(0, { $0 + $1 })
    XCTAssertTrue(nothing == 0)
    
  }

    XCTAssertTrue(numbers.count == 9)
    XCTAssertTrue(numbers.asSequence().droplast().asArray().count == 8)
    
    XCTAssertTrue(emptyStrings.asSequence().droplast().asArray().count == 0)
    
  }
  
