input: Write a function to calculate the distance between two points on a two-dimensional plane given their coordinates. If the coordinates are invalid (e.g., non-numeric), return -1. Otherwise, return the calculated distance.
  assert calculate_distance(3, 4, -9, -2) == 13.0
  assert calculate_distance(0, 0, 0, 0) == 0.0
  assert calculate_distance(1, 1, 4, 5) == 5.0
  assert calculate_distance("a", 4, -9, -2) == -1
  assert calculate_distance(3, 4, "b", -2) == -1
output: def calculate_distance(x1, y1, x2, y2):
      if not (isinstance(x1, (int, float)) and isinstance(y1, (int, float)) and isinstance(x2, (int, float)) and isinstance(y2, (int, float))):
          return -1
      return ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5