class_docstr: tick at every integer mapping of the string data
class_docstr_tok: ["tick","at","every","integer","mapping","of","the","string","data"]
code: def __call__(self):
      return list(self._units.values())
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from collections import OrderedDict
  import itertools
  import six
  import numpy
  import matplotlib.units
  import matplotlib.ticker
  from distutils.version import LooseVersion
label_desc: Use image node_id 2 for calling the StrCategoryLocator obj's underlying member method code with example usage: obj.__call__() and returns: list