human
Solve the following python programming problem given the following code:
def __init__(self, label = None, validators = None, base_path = None, relative_path = None, namegen = None, allowed_extensions = None, max_size = None, thumbgen = None, thumbnail_size = None, permission = 438, url_relative_path = None, endpoint = 'static', **kwargs) : 
    '
            Constructor.

            :param label:
                Display label
            :param validators:
                Validators
            :param base_path:
                Absolute path to the directory which will store files
            :param relative_path:
                Relative path from the directory. Will be prepended to the file name for uploaded files.
                Flask-Admin uses `urlparse.urljoin` to generate resulting filename, so make sure you have
                trailing slash.
            :param namegen:
                Function that will generate filename from the model and uploaded file object.
                Please note, that model is "dirty" model object, before it was committed to database.

                For example::

                    import os.path as op

                    def prefix_name(obj, file_data):
                        parts = op.splitext(file_data.filename)
                        return secure_filename(\'file-%s%s\' % parts)

                    class MyForm(BaseForm):
                        upload = FileUploadField(\'File\', namegen=prefix_name)

            :param allowed_extensions:
                List of allowed extensions. If not provided, then gif, jpg, jpeg, png and tiff will be allowed.
            :param max_size:
                Tuple of (width, height, force) or None. If provided, Flask-Admin will
                resize image to the desired size.
            :param thumbgen:
                Thumbnail filename generation function. All thumbnails will be saved as JPEG files,
                so there\'s no need to keep original file extension.

                For example::

                    import os.path as op

                    def thumb_name(filename):
    ...

    
    

    Fix the buggy line: if (not thumbgen) :
assistant
#Here is Python program to fix the buggy line: if (not thumbgen) :
.

if (not allowed_extensions) :