# General class axioms¶

General class axioms are axioms of the form “A is a B” where “A” is not a named class, but a class construct (e.g. an intersection, a union or a restriction).

## Creating a general class axiom¶

One can create a general class axiom as follows:

```
>>> with onto:
... gca = GeneralClassAxiom(onto.Disorder & onto.has_location.some(onto.Heart)) # Left side
... gca.is_a.append(onto.CardiacDisorder) # Right side
```

The GeneralClassAxiom class take as parameter the left side class construct.

The right side is available as the .is_a attribute. Notice that one may add several right sides, by calling is_a.append multiple times.

The left side is available as the .left_side attribute.

## Accessing general class axioms¶

One can list general class axioms with Ontology.general_class_axioms:

```
>>> gcas = list(onto.general_class_axioms())
```

One can then test the left side by comparison, for example:

```
>>> searched_left_side = onto.Disorder & onto.has_location.some(onto.Heart)
>>> for gca in gcas:
... if gca.left_side == searched_left_side: print("Found!")
```