title: Printing all the Python built-in sub-modules and functions of a builtin module
body: <p>I want to print all the available functions and sub-modules in a built-in module.
  For example:</p>
  
  <pre><code>dir(__import__("sys"))
  </code></pre>
  
  <p>It gives a list of classes and methods.</p>
  
  <pre><code>['__displayhook__',
  '__doc__',
  '__egginsert',
  '__excepthook__',
  '__name__',
  '__package__',
  '__plen',
  '__stderr__',
  '__stdin__',
  '__stdout__',
  'argv',
  'builtin_module_names',
  'byteorder',
  'call_tracing',
  'stdin',
  'stdout',
  'subversion',
  'version',
  'version_info',
  'warnoptions',
  'winver'] ...etc
  </code></pre>
  
  <p>but what i want is , I want to check all the available methods inside the class <strong>sys.stdin</strong> i.e.</p>
  
  <p><strong>sys.stdin</strong> constains the following functions like    </p>
  
  <pre><code>sys.stdin.close  
  sys.stdin.name       
  sys.stdin.softspace  
  sys.stdin.readline  
  sys.stdin.readlines  
  sys.stdin.seek  ...etc
  </code></pre>
  
  <p>So how to print all the availbale methods of a sub-module class.<br>
  I'm curious on how to implement this.<br>
  Thanks.<br>
  EDIT:</p>
  
  <pre><code>module_name = "sys" #module is taken from the user
  smod ="stdin" # select the desire sub-module
  param = module_name + smod
  def printFns(param):
       #code to print all the available functions
  </code></pre>