def _call_api_on_func(cls, func):
        """ Decorator for forming the api call with the arguments of the
        function, it works by taking the arguments given to the function
        and building the url to call the api on it

        Keyword Arguments:
            func:  The function to be decorated
        """

        # Argument Handling
        if sys.version_info[0] < 3:
            # Deprecated since version 3.0
            argspec = inspect.getargspec(func)
        else:
            argspec = inspect.getfullargspec(func)
        try:
            # Asumme most of the cases have a mixed between args and named
            # args
            positional_count = len(argspec.args) - len(argspec.defaults)
            defaults = dict(
                zip(argspec.args[positional_count:], argspec.defaults))
        except TypeError:
            if argspec.args:
                # No defaults
                positional_count = len(argspec.args)
                defaults = {}
            elif argspec.defaults:
                # Only defaults
                positional_count = 0
                defaults = argspec.defaults
        # Actual decorating

        @wraps(func)
        def _call_wrapper(self, *args, **kwargs):
            used_kwargs = kwargs.copy()
            # Get the used positional arguments given to the function
            used_kwargs.update(zip(argspec.args[positional_count:],
                                   args[positional_count:]))
            # Update the dictionary to include the default parameters from the
            # function
            used_kwargs.update({k: used_kwargs.get(k, d)
                                for k, d in defaults.items()})
            # Form the base url, the original function called must return
            # the function name defined in the alpha vantage api and the data
            # key for it and for its meta data.
            function_name, data_key, meta_data_key = func(
                self, *args, **kwargs)
            url = "{}function={}".format(AlphaVantage._ALPHA_VANTAGE_API_URL,
                                         function_name)
            for idx, arg_name in enumerate(argspec.args[1:]):
                try:
                    arg_value = args[idx]
                except IndexError:
                    arg_value = used_kwargs[arg_name]
                if 'matype' in arg_name and arg_value:
                    # If the argument name has matype, we gotta map the string
                    # or the integer
                    arg_value = self.map_to_matype(arg_value)
                if arg_value:
                    # Discard argument in the url formation if it was set to
                    # None (in other words, this will call the api with its
                    # internal defined parameter)
                    if isinstance(arg_value, tuple) or isinstance(arg_value, list):
                        # If the argument is given as list, then we have to
                        # format it, you gotta format it nicely
                        arg_value = ','.join(arg_value)
                    url = '{}&{}={}'.format(url, arg_name, arg_value)
            # Allow the output format to be json or csv (supported by
            # alphavantage api). Pandas is simply json converted.
            if 'json' in self.output_format.lower() or 'csv' in self.output_format.lower():
                oformat = self.output_format.lower()
            elif 'pandas' in self.output_format.lower():
                oformat = 'json'
            else:
                raise ValueError("Output format: {} not recognized, only json,"
                                 "pandas and csv are supported".format(
                                     self.output_format.lower()))
            if self._append_type:
                url = '{}&apikey={}&datatype={}'.format(url, self.key, oformat)
            else:
                url = '{}&apikey={}'.format(url, self.key)
            return self._handle_api_call(url), data_key, meta_data_key
        return _call_wrapper