def _addplugin(plugin, _larch=None, **kws):
    if _larch is None:
        raise Warning("cannot add plugins. larch broken?")
    write = _larch.writer.write
    errmsg = 'is not a valid larch plugin\n'
    pjoin = os.path.join
    path = site_config.plugins_path
    _sysconf = _larch.symtable._sys.config
    if not hasattr(_larch.symtable._sys, 'import_ok'):
        _larch.symtable._sys.import_ok  = True
    if not _larch.symtable._sys.import_ok:
        return

    if not hasattr(_sysconf, 'plugins_path'):
        _sysconf.plugins_path = site_config.plugins_path

    def _find_plugin(plugin, p_path):
        """find the plugin from path
        returns True, package name for packages
                False, (fh, modpath, desc) for imported modules
                None, None for Not Found
        """
        if not _larch.symtable._sys.import_ok:
            return

        if plugin == '__init__':
            return None, None
        mod, is_pkg = None, False
        try:
            mod = imp.find_module(plugin, [p_path])
        except ImportError:
            is_pkg = os.path.isdir(pjoin(p_path, plugin))

        if is_pkg or (mod is not None and
                      mod[2][2] == imp.PKG_DIRECTORY):
            return True, pjoin(p_path, plugin)
        elif mod is not None:
            return False, mod
        else:
            return None, None

    def on_error(msg):
        _larch.raise_exception(None, exc=ImportError, msg=msg)
        _larch.symtable._sys.import_ok = False

    def _check_requirements(ppath):
        """check for requirements.txt, return True only if all
        requirements are met
        """
        req_file = os.path.abspath(os.path.join(ppath, PLUGINSREQ))
        if not os.path.exists(req_file):
            return True
        if os.path.exists(req_file):
            with open(req_file, 'r') as fh:
                for line in fh.readlines():
                    line = line[:-1]
                    if line.startswith('#'):  continue
                    match = REQMATCH(line)
                    if match is None:
                        continue
                    ok = False
                    modname, cmp, req_vers = match.groups()
                    try:
                        mod = __import__(modname)
                        vers = getattr(mod, '__version__', None)
                        if   cmp == '>':  ok = vers >  req_vers
                        elif cmp == '<':  ok = vers <  req_vers
                        elif cmp == '>=': ok = vers >= req_vers
                        elif cmp == '<=': ok = vers <= req_vers
                        elif cmp == '==': ok = vers == req_vers
                        elif cmp == '=':  ok = vers == req_vers
                        elif cmp == '!=': ok = vers != req_vers
                    except:
                        ok = False
                    if not ok:
                        return False
        return True

    def _plugin_file(plugin, path=None):
        "defined here to allow recursive imports for packages"
        fh = None
        if plugin == '__init__':
            return
        if not _larch.symtable._sys.import_ok:
            return

        if path is None:
            try:
                path = _larch.symtable._sys.config.plugins_path
            except:
                path = site_config.plugins_path

        for p_path in path:
            # print(" -- find_plugin ", plugin)
            is_pkg, mod = _find_plugin(plugin, p_path)
            if is_pkg is not None:
                break
        if is_pkg is None and mod is None:
            write('Warning: plugin %s not found\n' % plugin)
            return False

        retval = True
        if is_pkg:
            if _check_requirements(plugin):
                filelist = []
                if PLUGINSTXT in sorted(os.listdir(mod)):
                    pfile = os.path.abspath(os.path.join(mod, PLUGINSTXT))
                    try:
                        with open(pfile, 'r') as pluginsfile:
                            for name in pluginsfile:
                                name = name[:-1].strip()
                                if (not name.startswith('#') and
                                    name.endswith('.py') and len(name) > 3):
                                    filelist.append(name)
                    except:
                        write("Warning:: Error reading plugin file:\n %s\n" %
                              pfile)
                if len(filelist) == 0:
                    for fname in sorted(os.listdir(mod)):
                        if fname.endswith('.py') and len(fname) > 3:
                            filelist.append(fname)

                retvals = []
                for fname in filelist:
                    if not _larch.symtable._sys.import_ok:
                        return
                    try:
                        ret =  _plugin_file(fname[:-3], path=[mod])
                    except:
                        err, exc, tback = sys.exc_info()
                        write('Warning: %s is =not= a valid plugin\n' %
                              pjoin(mod, fname))
                        write("   error:  %s\n" % (repr(sys.exc_info()[1])))
                        ret = False
                        _larch.symtable._sys.import_ok = False
                    retvals.append(ret)
                retval = all(retvals)
        else:
            fh, modpath, desc = mod
            try:
                out = imp.load_module(plugin, fh, modpath, desc)
                _larch.symtable.add_plugin(out, on_error, **kws)
            except:
                err, exc, tback = sys.exc_info()
                lineno = getattr(exc, 'lineno', 0)
                offset = getattr(exc, 'offset', 0)
                etext  = getattr(exc, 'text', '')
                emsg   = getattr(exc, 'message', '')
                try:
                    write(traceback.print_tb(tback))
                except:
                    pass
                write("""Python Error at plugin '%s', line %d
  %s %s^
%s: %s\n""" % (modpath, lineno, etext, ' '*offset, err.__name__, emsg))
                retval = False
                _larch.symtable._sys.import_ok = False

        if _larch.error:
            retval = False
            err = _larch.error.pop(0)
            fname, lineno = err.fname, err.lineno
            output = ["Error Adding Plugin %s from file %s" % (plugin, fname),
                      "%s" % (err.get_error()[1])]

            for err in _larch.error:
                if ((err.fname != fname or err.lineno != lineno) and
                    err.lineno > 0 and lineno > 0):
                    output.append("%s" % (err.get_error()[1]))
            write('\n'.join(output))

        if fh is not None:
            fh.close()
        return retval

    return _plugin_file(plugin)
Performs pressing a mouse button down and then immediately releasing it.
dataset/ETHPy150Open xraypy/xraylarch/lib/builtins.py/_addplugin--crossover with--dataset/ETHPy150Open asweigart/pyautogui/pyautogui/__init__.py/click