code: def kwargs_to_matrix(**kwargs):
      
      matrix = np.eye(4)
      if 'matrix' in kwargs:
          # a matrix takes precedence over other options
          matrix = kwargs['matrix']
      elif 'quaternion' in kwargs:
          matrix = transformations.quaternion_matrix(kwargs['quaternion'])
      elif ('axis' in kwargs) and ('angle' in kwargs):
          matrix = transformations.rotation_matrix(kwargs['angle'],
                                                   kwargs['axis'])
      else:
          raise ValueError('Couldn\'t update transform!')
  
      if 'translation' in kwargs:
          # translation can be used in conjunction with any of the methods of
          # specifying transforms. In the case a matrix and translation are passed,
          # we add the translations together rather than picking one.
          matrix[0:3, 3] += kwargs['translation']
      return matrix
docs: Turn a set of keyword arguments into a transformation matrix.