code: def unit_normal(pt_a, pt_b, pt_c):
      
      x_val = np.linalg.det([[1, pt_a[1], pt_a[2]], [1, pt_b[1], pt_b[2]], [1, pt_c[1], pt_c[2]]])
      y_val = np.linalg.det([[pt_a[0], 1, pt_a[2]], [pt_b[0], 1, pt_b[2]], [pt_c[0], 1, pt_c[2]]])
      z_val = np.linalg.det([[pt_a[0], pt_a[1], 1], [pt_b[0], pt_b[1], 1], [pt_c[0], pt_c[1], 1]])
      magnitude = (x_val**2 + y_val**2 + z_val**2)**.5
      mag = (x_val/magnitude, y_val/magnitude, z_val/magnitude)
      if magnitude < 0.00000001:
          mag = (0, 0, 0)
      return mag
docs: unit normal vector of plane defined by points pt_a, pt_b, and pt_c