code: def decode_keys(store, encoding='utf-8'):
      
      keys = store.keys()
      for key in keys:
          if hasattr(key, 'decode'):
              decoded = key.decode(encoding)
              if key != decoded:
                  store[key.decode(encoding)] = store[key]
                  store.pop(key)
      return store
docs: If a dictionary has keys that are bytes decode them to a str.
  
      Parameters
      ---------
      store : dict
        Dictionary with data
  
      Returns
      ---------
      result : dict
        Values are untouched but keys that were bytes
        are converted to ASCII strings.
  
      Example
      -----------
      In [1]: d
      Out[1]: {1020: 'nah', b'hi': 'stuff'}
  
      In [2]: trimesh.util.decode_keys(d)
      Out[2]: {1020: 'nah', 'hi': 'stuff'}