assert_all_are_existing
                        Does the variable exist?
assert_all_are_valid_variable_names
                        Is the string a valid variable name?
assert_has_arg          Does the current call have an argument?
assert_is_binding_locked
                        Is the binding of a variable locked?
assert_is_debugged      Is the input function being debugged?
assert_is_if_condition
                        Is suitable to be used as an if condition
assert_is_loaded        Is the input a symbol in a loaded DLL?
assert_is_valid_r_code
                        Is the input valid R code?
is_error_free           Does the code run without throwing an error?
