code: def isRotationMatrix(R):
      """checks if a matrix is a valid rotation matrix(whether orthogonal or not)"""
      Rt = np.transpose(R)
      shouldBeIdentity = np.dot(Rt, R)
      I = np.identity(3, dtype=R.dtype)
      n = np.linalg.norm(I - shouldBeIdentity)
      return n < 1e-6
  
file_path: insightface/reconstruction/ostec/utils/ganfit_camera.py
imports: import numpy
  import math
label_desc: Use image node_id 6 for calling a global function with example usage: isRotationMatrix(R) and returns: unknown