Fetches ad params. Unlike other selectors, does not support filtering or
sorting.
Typical usage:
var adParamSelector = AdsApp.adParams();
var adParamIterator = adParamSelector.get();
while (adParamIterator.hasNext()) {
  var adParam = adParamIterator.next();
}
Related:
  Methods:
  
  get()
  Fetches the requested ad params and returns an iterator.  
Return values:
  
  orderBy(orderBy)
  Specifies the ordering of the resulting entities. The 
orderBy
parameter can have one of the following forms:
  orderBy("ad_parameter.parameter_index") - orders results
by index, in ascending order.
  orderBy("ad_parameter.parameter_index ASC") - orders
results by index, in ascending order.
  orderBy("ad_parameter.insertion_text DESC") - orders
results by insertion text, in descending order.
  Arguments:
  
    | Name | Type | Description | 
    
      | orderBy | 
      String | 
      Ordering to apply. | 
    
  
  Return values:
  
  withCondition(condition)
  Adds the specified condition to the selector in order to narrow down the
results.
Multiple conditions can be added to the same selector:
selector = selector
    .withCondition("ad_parameter.parameter_index = 1")
    .withCondition("ad_parameter.insertion_text = '$99'");
All specified conditions are 
AND-ed together. The above
example will retrieve ad params whose index is 1 and insertion text is
'$99'.
The condition passed into this method must be of the following form:
"COLUMN_NAME OPERATOR VALUE"
  Arguments:
  
    | Name | Type | Description | 
    
      | condition | 
      String | 
      Condition to add to the selector. | 
    
  
  Return values:
  
  withLimit(limit)
  Specifies limit for the selector to use. For instance,
withLimit(50) returns only the first 50 entities.  
Arguments:
  
    | Name | Type | Description | 
    
      | limit | 
      int | 
      How many entities to return. | 
    
  
  Return values: