input: Write a function to calculate the distance between two points given their coordinates in a 2D plane. The function should take four arguments: x1, y1 for the coordinates of the first point, and x2, y2 for the coordinates of the second point. The function should return the distance between the two points.
  assert math.isclose(distance_between_points(2, 7, 4, 9), 2.8284271247461903)
  assert math.isclose(distance_between_points(0, 0, 3, 4), 5.0)
output: def distance_between_points(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5