a tenant can be created with name, age, and cred
an apartment can be initialized with number, sq_feet, num_beds, num_baths, and rent
tenants with sufficient credit can be added to an apartment provided there is vacancy
tenant can be removed provided they are present in apartment
can remove all tenants
can calculate average cred of all tenants
can determine cred rating based on avg_cred
move apartment spec into independent spec file
create a building with an address
add apartment to building
remove apartment if found and either empty or evicting
can calculate total sq footage
calculate total monthly revenue
return list of all tenants