class_docstr: Convert a tract file into a map of the fraction of tracks to enter
  each voxel - also known as a tract density image (TDI) - in MRtrix's
  image format (.mif). This can be viewed using MRview or converted to
  Nifti using MRconvert.
  
  Example
  -------
  
  >>> import nipype.interfaces.mrtrix as mrt
  >>> tdi = mrt.Tracks2Prob()
  >>> tdi.inputs.in_file = 'dwi_CSD_tracked.tck'
  >>> tdi.inputs.colour = True
  >>> tdi.run()                                       # doctest: +SKIP
code: def _gen_filename(self, name):
      if name == "out_filename":
          return self._gen_outfilename()
      else:
          return None
  
imports: import os
  import os.path
  from ...utils.filemanip import split_filename
  from ..base import CommandLineInputSpec, CommandLine, traits, TraitedSpec, File, isdefined
label_desc: Use image node_id 2 for calling the Tracks2Prob obj's underlying member method code with example usage: obj._gen_filename(name) and returns: self, None