code: def compute_proj_evoked(
      evoked,
      n_grad=2,
      n_mag=2,
      n_eeg=2,
      desc_prefix=None,
      meg="separate",
      verbose=None,
  ):
      """Compute SSP (signal-space projection) vectors on evoked data.
  
      %(compute_ssp)s
  
      Parameters
      ----------
      evoked : instance of Evoked
          The Evoked obtained by averaging the artifact.
      %(n_proj_vectors)s
      desc_prefix : str | None
          The description prefix to use. If None, one will be created based on
          tmin and tmax.
  
          .. versionadded:: 0.17
      meg : str
          Can be ``'separate'`` (default) or ``'combined'`` to compute projectors
          for magnetometers and gradiometers separately or jointly.
          If ``'combined'``, ``n_mag == n_grad`` is required and the number of
          projectors computed for MEG will be ``n_mag``.
  
          .. versionadded:: 0.18
      %(verbose)s
  
      Returns
      -------
      projs : list of Projection
          List of projection vectors.
  
      See Also
      --------
      compute_proj_raw, compute_proj_epochs
      """
      data = np.dot(
          evoked.data, evoked.data.T
      )  # compute data covariance
      if desc_prefix is None:
          desc_prefix = "%-.3f-%-.3f" % (
              evoked.times[0],
              evoked.times[-1],
          )
      return _compute_proj(
          data, evoked.info, n_grad, n_mag, n_eeg, desc_prefix, meg=meg
      )
  
imports: import numpy
  from ._fiff.constants import FIFF
  from ._fiff.open import fiff_open
  from ._fiff.pick import _picks_to_idx, pick_types, pick_types_forward
  from ._fiff.proj import Projection, _has_eeg_average_ref_proj, _read_proj, _write_proj, make_eeg_average_ref_proj, make_projector
  from ._fiff.write import start_and_end_file
  from .cov import _check_n_samples
  from .epochs import Epochs
  from .event import make_fixed_length_events
  from .fixes import _safe_svd
  from .forward import _subject_from_forward, convert_forward_solution, is_fixed_orient
  from .parallel import parallel_func
  from .source_estimate import _make_stc
  from .utils import _check_fname, _check_option, _validate_type, check_fname, logger, verbose
label_desc: Use image node_id 6 for calling a global function with example usage: compute_proj_evoked(evoked, n_grad, n_mag, n_eeg, desc_prefix, meg, verbose) and returns: _compute_proj