title: Cohesive block of code
body: <p>I'm currently reading about modules in angular 2. In Angular documentation there is statement:</p>
  
  <p>"A typical module is a cohesive block of code dedicated to a single purpose."</p>
  
  <p>I want to figure out what they mean by a cohesive block of code?</p>
  
  <p>Can someone explain it simply? </p>
  
  <p>I googled, but I didn't found any good explanation which is simple.
  Thanks!</p>