input: Write a function to calculate the distance between two points on a two-dimensional plane. The function should take four parameters (x1, y1, x2, y2) representing the coordinates of the two points and return the distance as a float. The distance should be calculated using the Euclidean distance formula: sqrt((x2 - x1)^2 + (y2 - y1)^2).
  assert calculate_distance(3, 4, -9, -2) == 13.0
  assert calculate_distance(0, 0, 1, 1) == 1.4142135623730951
  assert calculate_distance(1, 1, 1, 1) == 0.0
  assert calculate_distance(-4, -5, -4, -5) == 0.0
output: def calculate_distance(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5