code: def extractUnits(self, inp):
          
          inp = self._preprocess(inp)
  
          units = []
          description = ""
          for w in inp.split(' '):
              if self.isValidUnit(w) or w == '/':
                  if description:
                      description += " "
                  description += w
              else:
                  if description:
                      units.append(description)
                  description = ""
  
          if description:
              units.append(description)
          return units
docs: Collects all the valid units from an inp string. Works by
          appending consecutive words from the string and cross-referncing
          them with a set of valid units.
  
          Args:
              inp (str): Some text which hopefully contains descriptions
                  of different units.
  
          Returns:
              A list of strings, each entry in which is a valid quantities
              unit.