def METHOD_NAME(extras=None, size=None,
                  trajectory=False, velocities=False, forces=False):
    """Make a dummy reference Universe
    Allows the construction of arbitrary-sized Universes. Suitable for
    the generation of structures for output.
    Preferable for testing core components because:
      * minimises dependencies within the package
      * very fast compared to a "real" Universe
    Parameters
    ----------
    extras : list of strings, optional
      extra attributes to add to Universe:
      u = make_Universe(('masses', 'charges'))
      Creates a lightweight Universe with only masses and charges.
    size : tuple of int, optional
      number of elements of the Universe (n_atoms, n_residues, n_segments)
      defaults to (125, 25, 5)
    trajectory : bool, optional
      create a fake Reader object attached to Universe, default False
    velocities : bool, optional
      if the fake Reader provides velocities, default False
    force : bool, optional
      if the fake Reader provides forces, default False
    Returns
    -------
    MDAnalysis.core.universe.Universe object
    """
    import MDAnalysis as mda
    if size is None:
        size = _N_ATOMS, _N_RESIDUES, _N_SEGMENTS
    n_atoms, n_residues, n_segments = size
    u = mda.Universe.empty(
        # topology things
        n_atoms=n_atoms,
        n_residues=n_residues,
        n_segments=n_segments,
        atom_resindex=np.repeat(
            np.arange(n_residues), n_atoms // n_residues),
        residue_segindex=np.repeat(
            np.arange(n_segments), n_residues // n_segments),
        # trajectory things
        trajectory=trajectory,
        velocities=velocities,
        forces=forces,
    )
    if extras is None:
        extras = []
    for ex in extras:
        u.add_TopologyAttr(ex, values=_MENU[ex](size))
    if trajectory:
        ts = u.trajectory.ts
        ts.positions = np.arange(3 * n_atoms).reshape(n_atoms, 3)
        ts.frame = 0
        if velocities:
            ts.velocities = np.arange(3 * n_atoms).reshape(n_atoms, 3) + 100
        if forces:
            ts.forces = np.arange(3 * n_atoms).reshape(n_atoms, 3) + 10000
    return u