This function checks the input var map array
        to ensure the required input variables exist

def _check_lsm_input(self, data_var_map_array):
        """
        This function checks the input var map array
        to ensure the required input variables exist
        """
        REQUIRED_HMET_VAR_LIST = ['Prcp', 'Pres', 'Temp', 'Clod',
                                  'RlHm', 'Drad', 'Grad', 'WndS']

        # make sure all required variables exist
        given_hmet_var_list = []
        for gssha_data_var, lsm_data_var in data_var_map_array:
            gssha_data_hmet_name = self.netcdf_attributes[gssha_data_var]['hmet_name']

            if gssha_data_hmet_name in given_hmet_var_list:
                raise ValueError("Duplicate parameter for HMET variable {0}"
                                 .format(gssha_data_hmet_name))
            else:
                given_hmet_var_list.append(gssha_data_hmet_name)

        for REQUIRED_HMET_VAR in REQUIRED_HMET_VAR_LIST:
            if REQUIRED_HMET_VAR not in given_hmet_var_list:
                raise ValueError("ERROR: HMET param is required to continue "
                                 "{0} ...".format(REQUIRED_HMET_VAR))