code: def getCanonicalRep(record_cluster):
      
      canonical_rep = {}
  
      keys = record_cluster[0].keys()
  
      for key in keys:
          key_values = []
          for record in record_cluster:
              # assume non-empty values always better than empty value
              # for canonical record
              if record[key]:
                  key_values.append(record[key])
          if key_values:
              canonical_rep[key] = getCentroid(key_values, comparator)
          else:
              canonical_rep[key] = ''
  
      return canonical_rep
docs: Given a list of records within a duplicate cluster, constructs a
      canonical representation of the cluster by finding canonical
      values for each field