def compute_single_neuron_isis(spike_times, neuron_idx):
  """Compute a vector of ISIs for a single neuron given spike times.

  Args:
    spike_times (list of 1D arrays): Spike time dataset, with the first
      dimension corresponding to different neurons.
    neuron_idx (int): Index of the unit to compute ISIs for.

  Returns:
    isis (1D array): Duration of time between each spike from one neuron.
  """
  #############################################################################
  # Students: Fill in missing code (...) and comment or remove the next line
  raise NotImplementedError("Exercise: compute single neuron ISIs")
  #############################################################################

  # Extract the spike times for the specified neuron
  single_neuron_spikes = ...

  # Compute the ISIs for this set of spikes
  # Hint: the function np.diff computes discrete differences along an array
  isis = ...

  return isis