input: Write a python function to check if the given points are in a straight line.
  assert line_checker([[3,3], [2,2], [1,1]]) == True
  assert line_checker([[3,3], [2,2], [1,2]]) == False
  assert line_checker([[1,1], [2,2], [3,3], [4,4]]) == True
output: def line_checker(coordinates):
      if len(coordinates) < 3:
          return True
      
      (x0, y0), (x1, y1) = coordinates[:2]
      
      for x, y in coordinates[2:]:
          if (y1 - y0) * (x - x0) != (y - y0) * (x1 - x0):
              return False
      
      return True