code: public DynamoDBScanExpression withFilterConditionEntry(String attributeName, Condition condition) {
          if ( scanFilter == null )
              scanFilter = new HashMap<String, Condition>();
  
          scanFilter.put(attributeName, condition);
          return this;
      }
docs: Adds a new filter condition to the current scan filter and returns a
  pointer to this object for method-chaining.
  
  @param attributeName
  The name of the attribute on which the specified condition
  operates.
  @param condition
  The condition which describes how the specified attribute is
  compared and if a row of data is included in the results
  returned by the scan operation.