capybara/virtualenv/lib/python2.7/site-packages/jinja2/runtime.py
def call(__self, __obj, *args, **kwargs):
        """Call the callable with the arguments and keyword arguments
        provided but inject the active context or environment as first
        argument if the callable is a :func:`contextfunction` or
        :func:`environmentfunction`.
        """
        if __debug__:
            __traceback_hide__ = True

        # Allow callable classes to take a context
        fn = __obj.__call__
        for fn_type in ('contextfunction',
                        'evalcontextfunction',
                        'environmentfunction'):
            if hasattr(fn, fn_type):
                __obj = fn
                break

        if isinstance(__obj, _context_function_types):
            if getattr(__obj, 'contextfunction', 0):
                args = (__self,) + args
            elif getattr(__obj, 'evalcontextfunction', 0):
                args = (__self.eval_ctx,) + args
            elif getattr(__obj, 'environmentfunction', 0):
                args = (__self.environment,) + args
        try:
            return __obj(*args, **kwargs)
        except StopIteration:
            return __self.environment.undefined('value was undefined because '
                                                'a callable raised a '
                                                'StopIteration exception')
def call(__self, __obj, *args, **kwargs):
        """Call the callable with the arguments and keyword arguments
        provided but inject the active context or environment as first
        argument if the callable is a :func:`contextfunction` or
        :func:`environmentfunction`.
        """
        if __debug__:
            __traceback_hide__ = True

        # Allow callable classes to take a context
        fn = __obj.__call__
        for fn_type in ('contextfunction',
                        'evalcontextfunction',
                        'environmentfunction'):
            if hasattr(fn, fn_type):
                __obj = fn
                break

        if isinstance(__obj, _context_function_types):
            if getattr(__obj, 'contextfunction', 0):
                args = (__self,) + args
            elif getattr(__obj, 'evalcontextfunction', 0):
                args = (__self.eval_ctx,) + args
            elif getattr(__obj, 'environmentfunction', 0):
                args = (__self.environment,) + args
        try:
            return __obj(*args, **kwargs)
        except StopIteration:
            return __self.environment.undefined('value was undefined because '
                                                'a callable raised a '
                                                'StopIteration exception')
Call the callable with the arguments and keyword arguments
        provided but inject the active context or environment as first
        argument if the callable is a :func:`contextfunction` or
        :func:`environmentfunction`.