code: def get_label(parameter, ptype, flavor=None, mpl=None):
      
      # determine flavor
      if flavor is not None:
          if flavor not in ('latex', 'mathml'):
              raise Exception('flavor not recognized: {}'.format(flavor))
      else:
          if mpl is None:
              raise Exception('either the flavor or mpl must be provided')
          rendering = mpl.rcParams['text.usetex']
          if rendering:
              flavor = 'latex'
          else:
              flavor = 'mathml'
  
      # check if the requested label is present
      if parameter not in labels:
          raise Exception('parameter not known')
      if ptype not in labels[parameter]:
          raise Exception('ptype not known')
      if flavor not in labels[parameter][ptype]:
          raise Exception('flavor not known')
  
      return labels[parameter][ptype][flavor]
docs: Return the label of a given SIP parameter
  
      Parameters
      ----------
      parameter: string
          type of parameter, e.g. rmag|rpha|cre|cim
      ptype: string
          material|meas. Either return the material property (e.g. resistivity)
          or the measurement parameter (e.g., impedance)
      flavor: string, optional
          if set, must be one of latex|mathml. Return a label for latex
          processing, or for mathml processing
      mpl: matplotlib, optional
          if set, infer flavor from mpl.rcParams. Will not be used if flavor is
          set
  
      Returns
      -------
      label: string
          the requested label