Sketch a graph of function $f$ that satisfy all the following conditions
$f'(x)>0 \,\text{if} -3<x<3 \,\text{or}\, x>6 ;\\ f'(x)=e^{(2x+7)} \,\text{if} \,x<-3 ;\\ f'(x)=-3 \,\text{if}\, 3<x<6 ;\\ f''(x)>0 \,\text{if} \,0<x<3 ;\\ f''(x)<0 \,\text{if} -3<x<0\, \text{or} \,x>6 ;\\ \displaystyle\lim_{x\to -\infty} f(x)=-15 ;\\ \displaystyle\lim_{x\to\infty} f(x)=12 ;\\ f \,\text{is continuous on} (-\infty, \infty) ;\\ f \,\text{is not differentiable at}\, x=3 \,\text{and}\, x=6 ;\\ f(0)=f(6)=0$