code: def find_first(self, attr_name, resources, extra_prefix=''):
          
          prefix = self.name + '-' + (extra_prefix + '-' if extra_prefix else '')
          for res in resources:
              attr = getattr(res, attr_name)
              if attr.startswith(prefix):
                  return res
docs: Returns the boto object for the first resource in ``resources`` that
          belongs to this stack.  Uses the attribute specified by ``attr_name``
          to match the stack name.
  
          E.g.  An RDS instance for a stack named ``foo`` might be named
          ``foo-mydb-fis8932ifs``.  This call::
  
              find_first('id', conn.get_all_dbinstances())
  
          would return the boto.rds.dbinstance.DBInstance object whose ``id`` is
          ``foo-mydb-fis8932ifs``.
  
          Returns None if a matching resource is not found.
  
          If specified, ``extra_prefix`` is appended to the stack name prefix
          before matching.