mortality_rates_path: character. Path to Mortality rates in a .txt file.
TFR_path: character. Path to Fertility rates in a .txt file.
total_population_path: character. Path to Populations in a .txt file.
WRA_path: character. Path to Women of Reproductive Age in a .txt file.
omega_age: numeric. Maximum age.
horizon: numeric. The forecast horizon.
first_year_projection: numeric. Year for the base population.
Returns
netmigration_projection returns an object of class fmforecast with the forecast netmigration models and the components of demography::forecast.fdmpr().