<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def load_yaml(filename):
 """Read a YAML document from a file. If the file cannot be read or parsed, a ConfigReadError is raised. """

    try:
        with open(filename, 'rb') as f:
            return yaml.load(f, Loader=Loader)
    except (IOError, yaml.error.YAMLError) as exc:
        raise ConfigReadError(filename, exc)