* see dependencies *

In [1]:

```
import proveit
from proveit.logic import InSet, Equals, Boolean
from proveit import x, y
from proveit.logic.equality import sub_left_side_into
from proveit.logic.sets.enumeration import singleton_def
%proving in_singleton_is_bool
```

In [2]:

```
state1 = singleton_def.instantiate({x:x, y:y})
```

In [3]:

```
state2 = InSet(Equals(x,y), Boolean).prove()
```

In [4]:

```
state1.sub_left_side_into(state2).generalize([x,y])
```

In [5]:

```
%qed
```

Out[5]: