Q:

Include curve into a filldraw cycle

I have a question regarding asymptote drawing in LaTeX. I'm an absolute novice in using asymptote, and I could not find any help in the manuals I found online.
Here is the problem.
Starting from this simple code
\begin{asy}
  import patterns;

  size(6cm,0);
  draw(box((0,0), (2,1)));

  pen p=1.5bp+.9red;

  pair A=(0,0), B=(0,1), C=(0.7,1), D=(2,0.35),E=(2,0);

  add("shd",hatch(H=3mm,dir=SE,red));

  filldraw(A--B--C--D--E--cycle,pattern("shd"),p);
  \end{asy}

which works fine and shades a region confined with straight lines, I want to change the segment CD to a curve $f(x)=0.7/x$. This is my naive try:
\begin{asy}
  import patterns;
  import graph;

  size(6cm,0);
  draw(box((0,0), (2,1)));

  pen p=1.5bp+.9red;

  pair A=(0,0), B=(0,1), C=(0.7,1), D=(2,0.35), E=(2,0);

  real f(real x) {return 0.7/x}

  add("shd",hatch(H=3mm,dir=SE,red));

  filldraw(A--B--C--graph(f,0.7,2)--D--E--cycle,pattern("shd"),p);
\end{asy}

However, it doesn't work. 
Thank you in advance for you help. 

A:

For an Asymptote beginner, I'm impressed that you have solved all the difficult problems in your script!  You have only forgotten a semicolon in your return statement.
Thank you for the working and non-working example code!
\begin{asy}
  import patterns;
  import graph;

  size(6cm,0);
  draw(box((0,0), (2,1)));

  pen p=1.5bp+.9red;

  pair A=(0,0), B=(0,1), C=(0.7,1), D=(2,0.35), E=(2,0);

  real f(real x) { return 0.7/x; }  // <------ ADDED SEMICOLON HERE

  add("shd",hatch(H=3mm,dir=SE,red));

  filldraw(A--B--C--graph(f,0.7,2)--D--E--cycle,pattern("shd"),p);
\end{asy}

