<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def filter_filenames(filenames):
 """ Skip files with extentions in `FILE_EXCLUDE_EXTENTIONS` and filenames that contain `FILE_SKIP_PATTENRS`. """

    filenames_cleaned = []
    for filename in filenames:
        keep = True
        for pattern in FILE_EXCLUDE_EXTENTIONS:
            if filename.endswith(pattern):
                keep = False
        for pattern in FILE_SKIP_PATTENRS:   # This will reject exercises...
            if pattern in filename:
                keep = False
        if keep:
            filenames_cleaned.append(filename)
    return filenames_cleaned