How to be more specific while import style from external file? I am talking about method:
The goal is to import chosen styles only (one, few of them) nor all of them.
As you found out, the method is called "importStyles" not "importStyle".
One approach is to use the "properties" property to transfer the essentials of any native object.
Sub-objects such as the various settings and and options of object styles require extra steps, though.
myStyle.properties = otherStyle.properties;
You can also create a blank document, import the styles there and remove the non desired ones.
To keep connection with "Styles" I was looking for StylesRange option. InDesign UI is able to do it, since there are checkboxes in import window, thats why. If there is no script method way - thats OK. I just asked more experienced people before I step into monk room.