def colors(theme=None):
    """
Return dictionary of colors.

.. code-block:: python

  {
    'selection' : '...',
    'queued'    : '...',
  }

:options:

  **theme** ([``'dark'``] | ``<str>``)
    Select color-theme.
  """
    if theme == 'dark':
        return {'selection': '1;32;40', 'queued': '0;37'}
    return {'selection': '', 'queued': ''}
