Limit the fractional part

Calculus Level 3

Compute $\lim _{ x \rightarrow { { n }^{ - }} }{ \frac { { e }^{\{ x \} }-\{ x \} -1 }{ { \{ x \} }^{ 2 } } }$

Where $\{.\}$ represents the fractional part function and $n$ is an integer.