def is_LaTeX(flist,env,abspath):
    savedpath = modify_env_var(env, 'TEXINPUTS', abspath)
    paths = env['ENV']['TEXINPUTS']
    if SCons.Util.is_List(paths):
        pass
    else:
        paths = paths.split(os.pathsep)
    if savedpath is _null:
        try:
            del env['ENV']['TEXINPUTS']
        except KeyError:
            pass
    else:
        env['ENV']['TEXINPUTS'] = savedpath
    if Verbose:
        print("is_LaTeX search path ",paths)
        print("files to search :",flist)
    for f in flist:
        if Verbose:
            print(" checking for Latex source ",str(f))
        content = f.get_text_contents()
        if LaTeX_re.search(content):
            if Verbose:
                print("file %s is a LaTeX file" % str(f))
            return 1
        if Verbose:
            print("file %s is not a LaTeX file" % str(f))
        inc_files = [ ]
        inc_files.extend( include_re.findall(content) )
        if Verbose:
            print("files included by '%s': "%str(f),inc_files)
        for src in inc_files:
            srcNode = FindFile(src,['.tex','.ltx','.latex'],paths,env,requireExt=False)
            fileList = [srcNode,]
            if Verbose:
                print("FindFile found ",srcNode)
            if srcNode is not None:
                file_test = is_LaTeX(fileList, env, abspath)
            if file_test:
                return file_test
        if Verbose:
            print(" done scanning ",str(f))
    return 0