input: Write a function to calculate the distance between two points in a 2D plane. The function should take four parameters representing the x and y coordinates of the two points, and return the distance as a floating-point number. Use the Euclidean distance formula for the calculation.
  assert distance_between_points(2, 7, 4, 9)==2.8284271247461903
  assert distance_between_points(0, 0, 1, 1)==1.4142135623730951
  assert distance_between_points(1, 1, 1, 2)==1
  assert distance_between_points(3, 0, 0, 4)==5
  assert distance_between_points(0, 0, 0, 0)==0
output: def distance_between_points(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5