code: def merge_pmag_recs(self, old_recs):
          
          recs = {}
          recs = deepcopy(old_recs)
          headers = []
          for rec in recs:
              for key in list(rec.keys()):
                  if key not in headers:
                      headers.append(key)
          for rec in recs:
              for header in headers:
                  if header not in list(rec.keys()):
                      rec[header] = ""
          return recs
docs: Takes in a list of dictionaries old_recs and returns a list of
          dictionaries where every dictionary in the returned list has the
          same keys as all the others.
  
          Parameters
          ----------
          old_recs : list of dictionaries to fix
  
          Returns
          -------
          recs : list of dictionaries with same keys