Switch to Previous IFRAME Selenium Python

I am trying to switch to the previous frame.

In my code

1. I switch to a frame (BRCT1Frame),
2. Click a button that opens a new window
3. Switch to a new window
4. Switch to the frame inside of the window
5. Insert data & save which closes both the window and frame

However, there is a frame that is before the BRVT1Frame that I need to switch to.

Here is My Code:

BRT1Frame=driver.switch_to_frame(driver.find_element_by_tag_name("iframe"))
    buttons=driver.find_elements_by_css_selector("button")
    for button in buttons:
        if button.text.strip()=="Create Community":
            button.click()

    #A new pop up window causes me to switch windows
for handle in driver.window_handles:
    BRT=driver.switch_to_window(handle)
    print(BRT)

#then I switch frames
driver.switch_to_frame(driver.find_element_by_class_name("FormDialogIFrame"))   
driver.find_element_by_id("CommunityFormCommunityNameTextBox").send_keys("1st MEB STAFFEX")

save=driver.find_element_by_id("CommunityFormSaveButton").click()
#that popup closes now I have to switch to another frame

The frame I am trying to switch to code:

<iframe role="presentation" 
class="x-component x-window-item x-component-default"
src="/brvt?lang=en_US&amp;owf=true&amp;themeName=a_default&amp;
themeContrast=standard&amp;themeFontSize=12" 
name="{&quot;id&quot;:&quot;778a1259-bc80-602e-c0ad-16a3f9220516&quot;,&quot;containerVersion&quot;:&quot;7-GA&quot;,&quot;webContextPath&quot;:&quot;/owf&quot;,&quot;preferenceLocation&quot;:&quot;https://www.url,com;,&quot;relayUrl&quot;:&quot;https://url.com/55js/even/rpc_relay.uncompressed.html&quot;,&quot;lang&quot;:&quot;en_US&quot;,&quot;currentTheme&quot;:{&quot;themeName&quot;:&quot;a_default&quot;,&quot;themeContrast&quot;:&quot;standard&quot;,&quot;themeFontSize&quot;:12},&quot;55f&quot;:true,&quot;layout&quot;:&quot;desktop&quot;,&quot;url&quot;:&quot;/brvt&quot;,&quot;guid&quot;:&quot;260f0022-66de-a78b-3ce8-8de63a3bdbec&quot;,&quot;version&quot;:1,&quot;locked&quot;:false}" 
id="{&quot;id&quot;:&quot;778a1259-bc80-602e-c0ad-16a3f9220516&quot;}" 
frameborder="0"></iframe>

I have tried to do this:

driver.switch_to_frame(driver.find_element_by_tag_name("iframe"))

this worked but when I tried to click a drop down menu inside of the frame:

driver.find_element_by_css_selector("#OYk3vd6NKj1jbrnew > td.sub_item_text").click()

I have also tried:

 driver.switch_to_frame(driver.find_element_by_id("{"id":"778a1259-bc80-602e-c0ad-16a3f9220516"}")

I get an error that states that it is unable to locate the element. Suggestions?