returns the key, value pair of the arguments passed as a dict object

        Sample Usage
        ++++++++++++++
        .. code:: python

            from bast import Controller

            class MyController(Controller):
                def index(self):
                    data = self.only(['username'])

        Returns only the argument username and assigns it to the data variable.

def only(self, arguments):
        """
        returns the key, value pair of the arguments passed as a dict object

        Sample Usage
        ++++++++++++++
        .. code:: python

            from bast import Controller

            class MyController(Controller):
                def index(self):
                    data = self.only(['username'])

        Returns only the argument username and assigns it to the data variable.
        """
        data = {}
        if not isinstance(arguments, list):
            arguments = list(arguments)

        for i in arguments:
            data[i] = self.get_argument(i)
        return data