Arduino - "expected primary-expression before '.' token" Error

#include "Ultrasonic.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // put your setup code here, to run once:
  lcd.begin();
  Serial.begin(9600);
}
Ultrasonic ultrasonic(11, 12); //Ultrasonic ultrasonic(Trig,Echo);
void loop()
{
  int a = (Ultrasonic.Ranging(CM));
  if (a >= 15 && a < 20)
  { Serial.println("guvenli");
    lcd.print("guvenli");
    delay(500);
    lcd.clear();
    tone(3, 2000, 100);
    delay(500);
    noTone(3);
  }
  if (a >= 10 && a < 15) {
    Serial.println("guvenli dikkat");
    lcd.print("guvenli dikkat");
    delay(500);
    lcd.clear();
    tone(3, 2000, 50);
    delay(250);
    noTone(3);
  }
  if (a < 5)
  {
    Serial.println("vurdun");
    lcd.print("vurdun");
    delay(500);
    lcd.clear();**uıhhf
    tone(3, 2000, 50);
    delay(50);
    noTone(3);
  }
}

In this code i'm getting an error like this:

   C:\Users\*\AppData\Local\Temp\arduino_modified_sketch_113625\sketch_apr29a.ino: In function 'void loop()':

sketch_apr29a:19:22: error: expected primary-expression before '.' token

   int a = (Ultrasonic.Ranging(CM)); 

                      ^

exit status 1
expected primary-expression before '.' token