Add code and tests for 'is_integer' and 'is_float'
Add code and tests for 'equal' and 'equal_property'
Add code and tests for 'not_equal' and 'not_equal_property'
Add code and tests for 'greater_than' and 'greater_than_property'
Add code and tests for 'less_than' and 'less_than_property'
Add code and tests for 'greater_than_or_equal' and 'greater_than_or_equal_property'
Add code and tests for 'less_than_or_equal' and 'less_than_or_equal_property'
Add code and tests for 'between'