def create_cube(bm: 'bmesh.types.BMesh', size: float, matrix:
    'mathutils.Matrix', calc_uvs: bool) ->dict:
    """Creates a cube. 

    :param bm: The bmesh to operate on. 
    :type bm: 'bmesh.types.BMesh'
    :param size: size of the cube 
    :type size: float
    :param matrix: matrix to multiply the new geometry with 
    :type matrix: 'mathutils.Matrix'
    :param calc_uvs: calculate default UVs 
    :type calc_uvs: bool
    :return:  verts: output vertstype list of (bmesh.types.BMVert) 
    """
    pass
