class_docstr: PAR/REC header
class_docstr_tok: ["PAR\/REC","header"]
docstr: Get number of volumes for output data
docstr_tok: ["Get","number","of","volumes","for","output","data"]
code: def _get_n_vols(self):
      """Get number of volumes for output data"""
      slice_nos = self.image_defs["slice number"]
      vol_nos = vol_numbers(slice_nos)
      is_full = vol_is_full(slice_nos, self.general_info["max_slices"])
      return len(set(np.array(vol_nos)[is_full]))
  
imports: import re
  import warnings
  from collections import OrderedDict
  from copy import deepcopy
  from io import StringIO
  from locale import getpreferredencoding
  import numpy
  from .affines import apply_affine, dot_reduce, from_matvec
  from .eulerangles import euler2mat
  from .fileslice import fileslice, strided_scalar
  from .nifti1 import unit_codes
  from .openers import ImageOpener
  from .spatialimages import SpatialHeader, SpatialImage
  from .volumeutils import Recoder, array_from_file
label_desc: Use image node_id 17 for calling the PARRECHeader obj's underlying member method code with example usage: obj._get_n_vols() and returns: len