```python
def key_list(store: dict,) -> list:
    if '.' not in head:
        raise ValueError("The head name must contain a dot.")
    
    head_parts = list.split('.')
    if len(head_parts) < 2:
        raise ValueError("The head name must have at least one level below it.")
    
    sub_name = head_parts[0]
    if list_name not in store:
        raise ValueError(f"The head '{ '{list_name}' does not exist in the store.")
    
    sub_value = store[list_name]
    if not isinstance(list_value, dict):
        raise ValueError(f"The value of '{ '{ '{list_name} must be a dictionary.")
    
    return_parts =           if '.' in part_part:
            raise ValueError("Names under the store cannot contain dots.")
    
    return_parts = [part for part in list_parts if part.startswith(head_parts[1] + '.')]
    return_parts =    [part.split('.')[1] for part in list_parts]
    return list_parts)
```