code: def _number_desc_by_type(metadata, num_type):
      
      if num_type == PhoneNumberType.PREMIUM_RATE:
          return metadata.premium_rate
      elif num_type == PhoneNumberType.TOLL_FREE:
          return metadata.toll_free
      elif num_type == PhoneNumberType.MOBILE:
          return metadata.mobile
      elif (num_type == PhoneNumberType.FIXED_LINE or
            num_type == PhoneNumberType.FIXED_LINE_OR_MOBILE):
          return metadata.fixed_line
      elif num_type == PhoneNumberType.SHARED_COST:
          return metadata.shared_cost
      elif num_type == PhoneNumberType.VOIP:
          return metadata.voip
      elif num_type == PhoneNumberType.PERSONAL_NUMBER:
          return metadata.personal_number
      elif num_type == PhoneNumberType.PAGER:
          return metadata.pager
      elif num_type == PhoneNumberType.UAN:
          return metadata.uan
      elif num_type == PhoneNumberType.VOICEMAIL:
          return metadata.voicemail
      else:
          return metadata.general_desc
docs: Return the PhoneNumberDesc of the metadata for the given number type