code: def wall_of_name(self):
          '''
          Appends identifiers for the different databases (such as Entrez id's)
          and returns them. Uses the CrossRef class below.
          '''
          names = []
          if self.standard_name:
              names.append(self.standard_name)
          if self.systematic_name:
              names.append(self.systematic_name)
          names.extend([xref.xrid for xref in self.crossref_set.all()])
          for i in range(len(names)):
              names[i] = re.sub(nonalpha, '', names[i])
  
          names_string = ' '.join(names)
          if self.standard_name:
              names_string += ' ' + re.sub(num, '', self.standard_name)
          return names_strinf wall_of_name(self):
          '''
          Appends identifiers for the different databases (such as Entrez id's)
          and returns them. Uses the CrossRef class below.
          '''
          names = []
          if self.standard_name:
              names.append(self.standard_name)
          if self.systematic_name:
              names.append(self.systematic_name)
          names.extend([xref.xrid for xref in self.crossref_set.all()])
          for i in range(len(names)):
              names[i] = re.sub(nonalpha, '', names[i])
  
          names_string = ' '.join(names)
          if self.standard_name:
              names_string += ' ' + re.sub(num, '', self.standard_name)
          return names_string
docs: Appends identifiers for the different databases (such as Entrez id's)
          and returns them. Uses the CrossRef class below.