The power operator binds more tightly than unary operators on its left; it binds less tightly than unary operators on its right. The syntax is:
power: primary ["**" u_expr]
Thus, in an unparenthesized sequence of power and unary operators, the operators are evaluated from right to left (this does not constrain the evaluation order for the operands).
The power operator has the same semantics as the built-in pow() function, when called with two arguments: it yields its left argument raised to the power of its right argument. The numeric arguments are first converted to a common type. The result type is that of the arguments after coercion; if the result is not expressible in that type (as in raising an integer to a negative power, or a negative floating point number to a broken power), a TypeError exception is raised.