code: def infer_namespace(ac):
      
  
      namespaces = infer_namespaces(ac)
      if not namespaces:
          return None
      if len(namespaces) > 1:
          raise BioutilsError("Multiple namespaces possible for {}".format(ac))
      return namespaces[0]
docs: Infer the single namespace of the given accession
  
      This function is convenience wrapper around infer_namespaces().
      Returns:
        * None if no namespaces are inferred
        * The (single) namespace if only one namespace is inferred
        * Raises an exception if more than one namespace is inferred
  
      >>> infer_namespace("ENST00000530893.6")
      'ensembl'
  
      >>> infer_namespace("NM_01234.5")
      'refseq'
  
      >>> infer_namespace("A2BC19")
      'uniprot'
  
      N.B. The following test is disabled because Python 2 and Python 3
      handle doctest exceptions differently. :-(
      X>>> infer_namespace("P12345")
      Traceback (most recent call last):
      ...
      bioutils.exceptions.BioutilsError: Multiple namespaces possible for P12345
  
      >>> infer_namespace("BOGUS99") is None
      True