def pretty_atom(atom_name, default=None):
 if _use_unicode:
  return atoms_table[atom_name]
 else:
  if (default is not None):
   return default
  raise KeyError('only unicode')

def pretty_atom ( atom_name , default = None ) : if _use_unicode : return atoms_table [ atom_name ] else : if ( default is not None ) : return default raise KeyError ( 'only unicode' )
return pretty representation of an atom .