Verify the Identity Shown Below $$\sec ^ { 2 } \mu - \cot ^ { 2 } \left( \frac { \pi } { 2 } - \mu \right) = 1$$

Verify the identity shown below.
$$\sec ^ { 2 } \mu - \cot ^ { 2 } \left( \frac { \pi } { 2 } - \mu \right) = 1$$