code: def observation_placeholder(ob_space, batch_size=None, name='Ob'):
      '''
      Create placeholder to feed observations into of the size appropriate to the observation space
  
      Parameters:
      ----------
  
      ob_space: gym.Space     observation space
  
      batch_size: int         size of the batch to be fed into input. Can be left None in most cases.
  
      name: str               name of the placeholder
  
      Returns:
      -------
  
      tensorflow placeholder tensor
      '''
  
      assert isinstance(ob_space, Discrete) or isinstance(ob_space, Box) or isinstance(ob_space, MultiDiscrete), \
          'Can only deal with Discrete and Box observation spaces for now'
  
      dtype = ob_space.dtype
      if dtype == np.int8:
          dtype = np.uint8
  
      return tf.placeholder(shape=(batch_size,) + ob_space.shape, dtype=dtype, name=namef observation_placeholder(ob_space, batch_size=None, name='Ob'):
      '''
      Create placeholder to feed observations into of the size appropriate to the observation space
  
      Parameters:
      ----------
  
      ob_space: gym.Space     observation space
  
      batch_size: int         size of the batch to be fed into input. Can be left None in most cases.
  
      name: str               name of the placeholder
  
      Returns:
      -------
  
      tensorflow placeholder tensor
      '''
  
      assert isinstance(ob_space, Discrete) or isinstance(ob_space, Box) or isinstance(ob_space, MultiDiscrete), \
          'Can only deal with Discrete and Box observation spaces for now'
  
      dtype = ob_space.dtype
      if dtype == np.int8:
          dtype = np.uint8
  
      return tf.placeholder(shape=(batch_size,) + ob_space.shape, dtype=dtype, name=name)
docs: Create placeholder to feed observations into of the size appropriate to the observation space
  
      Parameters:
      ----------
  
      ob_space: gym.Space     observation space
  
      batch_size: int         size of the batch to be fed into input. Can be left None in most cases.
  
      name: str               name of the placeholder
  
      Returns:
      -------
  
      tensorflow placeholder tensor