docs: def pilatus_description_metadata(description):
      """Return metatata from Pilatus image description as dict.
  
      Return metadata from Pilatus pixel array detectors by Dectris, created
      by camserver or TVX software.
  
      >>> pilatus_description_metadata('# Pixel_size 172e-6 m x 172e-6 m')
      {'Pixel_size': (0.000172, 0.000172)}
  
      """
      result = {}
      if not description.startswith('# '):
          return result
      for c in '#:=,()':
          description = description.replace(c, ' ')
      for line in description.split('\n'):
          if line[:2] != '  ':
              continue
          line = line.split()
          name = line[0]
          if line[0] not in TIFF.PILATUS_HEADER:
              try:
                  result['DateTime'] = datetime.datetime.strptime(
                      ' '.join(line), '%Y-%m-%dT%H %M %S.%f')
              except Exception:
                  result[name] = ' '.join(line[1:])
              continue
          indices, dtype = TIFF.PILATUS_HEADER[line[0]]
          if isinstance(indices[0], slice):
              # assumes one slice
              values = line[indices[0]]
          else:
              values = [line[i] for i in indices]
          if dtype is float and values[0] == 'not':
              values = ['NaN']
          values = tuple(dtype(v) for v in values)
          if dtype == str:
              values = ' '.join(values)
          elif len(values) == 1:
              values = values[0]
          result[name] = values
      return result