Custom File Input Validation in Django

fileformat.py

from django.core.exceptions import ValidationError

'''
Custom file validation function
'''
def ValidFile(value):
    '''
    1 mb = 1,048,576 bytes
    15 mb = 15728640 bytes
    '''
    import os 
    ext = os.path.splitext(value.name)[1]
    filetype = ['.pdf','.docs','.odt','.docx']
    if ext.lower() in filetype:
        if value.size > 15728640: 
            raise ValidationError ('Sorry File size max upload 15MB')
        else:
            return value 
    else:
        raise ValidationError ('Sorry file type not Supported')

models.py

from django.db import models
# import your custom file format module
from .fileformat import ValidFile


class FileUplaod (models.Model):
    '''
    using the module in models 
    '''
    files = models.FileField(null=True,upload_to='files/',blank=True,validators=[ValidFile])
    
    def __str__(self):
        return self.files