code: def transpose_mat44(src_mat, transpose_mat=None):
      
  
      if not transpose_mat:
          transpose_mat = Matrix44()
  
      for i in range(4):
          for j in range(4):
              transpose_mat.data[i][j] = src_mat.data[j][i]
  
      return transpose_mat
docs: Create a transpose of a matrix.