How to use the xonsh.tools.XonshError function in xonsh

def stdout(self, value):
        if self._stdout is None:
            self._stdout = value
        elif value is None:
            pass
        else:
            safe_close(value)
            msg = "Multiple redirections for stdout for {0!r}"
            msg = msg.format(" ".join(self.args))
            raise XonshError(msg)

for name, param in inspect.signature(f).parameters.items():
        if (
            param.kind == param.POSITIONAL_ONLY
            or param.kind == param.POSITIONAL_OR_KEYWORD
        ):
            numargs += 1
        elif name in ALIAS_KWARG_NAMES and param.kind == param.KEYWORD_ONLY:
            numargs += 1
    if numargs < 6:
        return functools.partial(PROXIES[numargs], f)
    elif numargs == 6:
        # don't need to partial.
        return f
    else:
        e = "Expected proxy with 6 or fewer arguments for {}, not {}"
        raise XonshError(e.format(", ".join(ALIAS_KWARG_NAMES), numargs))

# redirect to fd
    if dest.startswith("&"):
        try:
            dest = int(dest[1:])
            if loc is None:
                loc, dest = dest, ""  # NOQA
            else:
                e = "Unrecognized redirection command: {}".format(r)
                raise XonshError(e)
        except (ValueError, XonshError):
            raise
        except Exception:
            pass
    mode = _MODES.get(mode, None)
    if mode == "r" and (len(orig) > 0 or len(dest) > 0):
        raise XonshError("Unrecognized redirection command: {}".format(r))
    elif mode in _WRITE_MODES and len(dest) > 0:
        raise XonshError("Unrecognized redirection command: {}".format(r))
    return orig, mode, dest

spec = SubprocSpec.build(cmd, captured=captured)
            spec.pipeline_index = i
            specs.append(spec)
            i += 1
    # now modify the subprocs based on the redirects.
    for i, redirect in enumerate(redirects):
        if redirect == "|":
            # these should remain integer file descriptors, and not Python
            # file objects since they connect processes.
            r, w = os.pipe()
            specs[i].stdout = w
            specs[i + 1].stdin = r
        elif redirect == "&" and i == len(redirects) - 1:
            specs[-1].background = True
        else:
            raise XonshError("unrecognized redirect {0!r}".format(redirect))
    # Apply boundary conditions
    _update_last_spec(specs[-1])
    return specs

spec = SubprocSpec.build(cmd, captured=captured)
            spec.pipeline_index = i
            specs.append(spec)
            i += 1
    # now modify the subprocs based on the redirects.
    for i, redirect in enumerate(redirects):
        if redirect == "|":
            # these should remain integer file descriptors, and not Python
            # file objects since they connect processes.
            r, w = os.pipe()
            specs[i].stdout = w
            specs[i + 1].stdin = r
        elif redirect == "&" and i == len(redirects) - 1:
            specs[-1].background = True
        else:
            raise XonshError("unrecognized redirect {0!r}".format(redirect))
    # Apply boundary conditions
    _update_last_spec(specs[-1])
    return specs

# redirect to fd
    if dest.startswith("&"):
        try:
            dest = int(dest[1:])
            if loc is None:
                loc, dest = dest, ""  # NOQA
            else:
                e = "Unrecognized redirection command: {}".format(r)
                raise XonshError(e)
        except (ValueError, XonshError):
            raise
        except Exception:
            pass
    mode = _MODES.get(mode, None)
    if mode == "r" and (len(orig) > 0 or len(dest) > 0):
        raise XonshError("Unrecognized redirection command: {}".format(r))
    elif mode in _WRITE_MODES and len(dest) > 0:
        raise XonshError("Unrecognized redirection command: {}".format(r))
    return orig, mode, dest

for name, param in inspect.signature(f).parameters.items():
        if (
            param.kind == param.POSITIONAL_ONLY
            or param.kind == param.POSITIONAL_OR_KEYWORD
        ):
            numargs += 1
        elif name in ALIAS_KWARG_NAMES and param.kind == param.KEYWORD_ONLY:
            numargs += 1
    if numargs < 6:
        return functools.partial(PROXIES[numargs], f)
    elif numargs == 6:
        # don't need to partial.
        return f
    else:
        e = "Expected proxy with 6 or fewer arguments for {}, not {}"
        raise XonshError(e.format(", ".join(ALIAS_KWARG_NAMES), numargs))

def _parse_redirects(r, loc=None):
    """returns origin, mode, destination tuple"""
    orig, mode, dest = _REDIR_REGEX.match(r).groups()
    # redirect to fd
    if dest.startswith("&"):
        try:
            dest = int(dest[1:])
            if loc is None:
                loc, dest = dest, ""  # NOQA
            else:
                e = "Unrecognized redirection command: {}".format(r)
                raise XonshError(e)
        except (ValueError, XonshError):
            raise
        except Exception:
            pass
    mode = _MODES.get(mode, None)
    if mode == "r" and (len(orig) > 0 or len(dest) > 0):
        raise XonshError("Unrecognized redirection command: {}".format(r))
    elif mode in _WRITE_MODES and len(dest) > 0:
        raise XonshError("Unrecognized redirection command: {}".format(r))
    return orig, mode, dest