>>> from numberplate import only_consonants

>>> only_consonants('7216 XBS')
True
>>> only_consonants('7TG4 TNT')
True
>>> only_consonants('7216 ABU')
False
>>> only_consonants('7216 TnT')
False
>>> only_consonants('7216 GH6')
False
>>> only_consonants('7652BCD')
True