input: Write a function that calculates the Euclidean distance between two points in a two-dimensional plane. The function should take four parameters representing the x and y coordinates of the two points and return the distance. Use the formula: distance = sqrt((x2 - x1)^2 + (y2 - y1)^2).
  
  
  assert calculate_distance(3, 4, -9, -2) == 13.0
  assert calculate_distance(0, 0, 3, 4) == 5.0
  
output: def calculate_distance(x1, y1, x2, y2):
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5