def _ref(<EOL>pname, conf=None, configurable=None, cname=None, path=None, history=<NUM_LIT:0><EOL>):
result = None<EOL>if configurable is not None:<EOL><INDENT>kwargs = {}<EOL>if conf is not None:<EOL><INDENT>kwargs['<STR_LIT>'] = conf<EOL><DEDENT>if path is not None:<EOL><INDENT>kwargs['<STR_LIT>'] = path<EOL><DEDENT>if conf is None:<EOL><INDENT>conf = configurable.getconf(**kwargs)<EOL><DEDENT><DEDENT>if conf is None:<EOL><INDENT>raise ParserError(<EOL>'<STR_LIT>'<EOL>)<EOL><DEDENT>result = conf.param(pname=pname, cname=cname, history=history)<EOL>return result<EOL>
Resolve a parameter value.

    :param Configuration conf: configuration to use.
    :param str pname: parameter name.
    :param Configurable configurable: configurable.
    :param str cname: category name.
    :param str path: conf path.
    :param int history: parameter history research.
    :return: parameter.
    :raises: ParserError if conf and configurable are None.