docs: def _file_prefix(
              self):
          """*Generate a file prefix based on the type of search for saving files to disk*
  
          **Return:**
              - ``prefix`` -- the file prefix
          """
          self.log.info('starting the ``_file_prefix`` method')
  
          if self.ra:
              now = datetime.now()
              prefix = now.strftime("%Y%m%dt%H%M%S%f_tns_conesearch_")
          elif self.name:
              prefix = self.name + "_tns_conesearch_"
          elif self.internal_name:
              prefix = self.internal_name + "_tns_conesearch_"
          elif self.discInLastDays:
              discInLastDays = str(self.discInLastDays)
              now = datetime.now()
              prefix = now.strftime(
                  discInLastDays + "d_since_%Y%m%d_tns_conesearch_")
  
          self.log.info('completed the ``_file_prefix`` method')
          return prefix