input: Write a function to identify the largest number in the given list. The function should return the largest number.
  assert identify_largest_number([1000, 506, 299, 620, 35])==1000
  assert identify_largest_number([1, 2, 3, 4, 5])==5
  assert identify_largest_number([0, 0, 0, 0])==0
  assert identify_largest_number([-1, -5, -3, -2])==-1
  assert identify_largest_number([])==None
output: def identify_largest_number(numbers):
      if not numbers:
          return None
      return max(numbers)