@classmethod<EOL><INDENT>def from_param(cls, param):<DEDENT>
if isinstance(param, cls):<EOL><INDENT>return param<EOL><DEDENT>if isinstance(param, list):<EOL><INDENT>return cls(param)<EOL><DEDENT>if param is None:<EOL><INDENT>return cls.from_environment()<EOL><DEDENT>return cls.from_string(param)<EOL>
Construct a CommandSpec from a parameter to build_scripts, which may
be None.