code: def convert_single(ID, from_type, to_type):
      '''Convenience function wrapper for convert. Takes a single ID and converts it from from_type to to_type.
         The return value is the ID in the scheme of to_type.'''
  
      if from_type not in converter_types:
          raise PubMedConverterTypeException(from_type)
      if to_type not in converter_types:
          raise PubMedConverterTypeException(to_type)
  
      results = convert([ID], from_type)
      if ID in results:
          return results[ID].get(to_type)
      else:
          return results[ID.upper()].get(to_typef convert_single(ID, from_type, to_type):
      '''Convenience function wrapper for convert. Takes a single ID and converts it from from_type to to_type.
         The return value is the ID in the scheme of to_type.'''
  
      if from_type not in converter_types:
          raise PubMedConverterTypeException(from_type)
      if to_type not in converter_types:
          raise PubMedConverterTypeException(to_type)
  
      results = convert([ID], from_type)
      if ID in results:
          return results[ID].get(to_type)
      else:
          return results[ID.upper()].get(to_type)
docs: Convenience function wrapper for convert. Takes a single ID and converts it from from_type to to_type.
         The return value is the ID in the scheme of to_type.