def METHOD_NAME(assign):
    value = assign.value
    if isinstance(value, ast.Num):
        return value.n
    if isinstance(value, ast.Str):
        return value.s
    if isinstance(value, ast.UnaryOp) and isinstance(value.op, ast.USub):
        return -value.operand.n
    raise AscconvParseError(f'Unexpected RHS of assignment: {value}')