Email validator fails unexpectedly if we give it anything else than a string #141
Description
Hi, while challenging our API with random input we noticed that the Email validator wasn't failing with a ValidationError when we give it the wrong input:
em = fe.validators.Email()
em.to_python(45)
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-19-4dfaedfd72a0> in <module>()
----> 1 em.to_python(45)
~/.pyenv/versions/3.6.5/envs/cmp/lib/python3.6/site-packages/formencode/api.py in to_python(self, value, state)
--> 475 value = tp(value, state)
~/.pyenv/versions/3.6.5/envs/cmp/lib/python3.6/site-packages/formencode/validators.py in _convert_to_python(self, value, state)
-> 1390 return value.strip()
AttributeError: 'int' object has no attribute 'strip'
Before starting to work on this, I was wondering if there is any reason that validators.Email inherit from FancyValidator and not from validators.String? In fact, changing this would fix this bug