Package konval :: Module typeval :: Class IsInstance
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Class IsInstance

source code

                 object --+    
                          |    
basevalidator.BaseValidator --+
                              |
                             IsInstance

Checks that values are instances of a list of classes or their subclasses.

For example:

>>> v = IsInstance (basestring)
>>> v('foo')
'foo'
>>> v(1)
Traceback (most recent call last):
...
ValueError: '1' type is not one of basestring
Instance Methods [hide private]
 
__init__(self, allowed_classes)
x.__init__(...) initializes x; see x.__class__.__doc__ for signature
source code
 
validate_value(self, value)
Check a value is of the desired form.
source code
 
make_validation_error_msg(self, bad_val, err)
Generate an error message for a validation problem.
source code

Inherited from basevalidator.BaseValidator: __call__, convert, convert_value, make_conversion_error_msg, raise_conversion_error, raise_validation_error, validate

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__, __subclasshook__

Properties [hide private]

Inherited from object: __class__

Method Details [hide private]

__init__(self, allowed_classes)
(Constructor)

source code 
x.__init__(...) initializes x; see x.__class__.__doc__ for signature
Overrides: object.__init__
(inherited documentation)

validate_value(self, value)

source code 

Check a value is of the desired form.

This is the workhorse method that is called by validate to check passed values. As such, errors are signalled by either by throwing a meaningful exception or by returning false. This is one of the obvious and easiest places to customize behaviour by overriding in a subclass.

Parameters:
  • value - value to be checked
Returns:
success of validation.
Overrides: basevalidator.BaseValidator.validate_value
(inherited documentation)

make_validation_error_msg(self, bad_val, err)

source code 

Generate an error message for a validation problem.

Parameters as per raise_validation_error. Override in subclass if need be, for more specific and meaningful messages.

Overrides: basevalidator.BaseValidator.make_validation_error_msg
(inherited documentation)