Execute the following command:

pip install validators

It's preferable to use pip within a virtual environment.

import validators
print(validators.email('someone@example.com'))

1. Either set the environment variable RAISE_VALIDATION_ERROR to True

   $ export RAISE_VALIDATION_ERROR=True
   $ python -c "from validators import url; print(url('https//bad_url'))"
   Traceback (most recent call last):
   File "<string>", line 1, in <module>
   File "/path/to/lib/validators/utils.py", line 87, in wrapper
       raise ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
   validators.utils.ValidationError: ValidationError(func=url, args={'value': 'https//bad_url'})

2. Or pass r_ve=True to each caller function:

   $ python -c "from validators.card import visa; print(visa('bad_visa_number', r_ve=True))"
   Traceback (most recent call last):
   File "<string>", line 1, in <module>
   File "/path/to/lib/validators/utils.py", line 87, in wrapper
       raise ValidationError(func, _func_args_as_dict(func, *args, **kwargs))
   validators.utils.ValidationError: ValidationError(func=visa, args={'value': 'bad_visa_number'})