Determine the file type and return it.

def determine_type(filename):
    '''Determine the file type and return it.'''
    ftype = magic.from_file(filename, mime=True).decode('utf8')
    if ftype == 'text/plain':
        ftype = 'text'
    elif ftype == 'image/svg+xml':
        ftype = 'svg'
    else:
        ftype = ftype.split('/')[1]
    return ftype