Timeout Waiting for Visible iframe - python-3.x

Question

I'm learning Selenium with Python, and attempting to write happy path flow for a website. Where I get stuck is a part of the flow where an iframe is automatically launched after clicking through a pop-up window. I've tried several different methods, but am unable to locate the frame, or wait for it appear. Either it's not found or times out.
WebDriverWait(driver, 5).until(EC.element_to_be_clickable((By.ID, 'continue- reservation'))).click()
# cvv2 form
WebDriverWait(driver, 5).until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'cvv_iframe')))
Error:
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.ID, 'cvv_iframe')))
File "/Users/anutter/venv/lib/python3.7/site-packages/selenium/webdriver/support/wait.py", line 80, in until
raise TimeoutException(message, screen, stacktrace)
selenium.common.exceptions.TimeoutException: Message:
HTML is as follows:
<div id="cpstaging" class="emptystage">
<div class="fixed h-v-centered new-preload" style="display: none;"><span class="fa fa-spinner f-50 f-grn fa-pulse"></span></div>
</div>
<div id="cvv-box" class="pad-30-lr">
<div id="enter-cvv-title" class="blk mar-20-b f-18 border-b pad-10-b">Enter CVV Code</div>
<iframe src="https://qa-hotels.ecbsn.com/cvv?oauth_token=u7q99%2Fe8I%2BkUrkLMr4dGR2t4gmcDbVtr&type=visa&src=web-desktop" id="cvv_iframe" name="cvv_iframe" width="430" height="160" frameborder="0" seamless="seamless" scrolling="no" sandbox="allow-same-origin allow-scripts allow-popups allow-forms"></iframe>
</div>
</div>
</div>
</div>

Answer 1

As per the HTML you have shared to access the elements within the <iframe> you have to:
Induce WebDriverWait for the desired frame to be available and switch to it using either of the Locator Strategies:
Using ID:
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.ID,"cvv_iframe")))
Using NAME:
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.NAME,"cvv_iframe")))
Using CSS_SELECTOR:
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.CSS_SELECTOR,"iframe#cvv_iframe[name='cvv_iframe']")))
Using XPATH:
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.XPATH,"//iframe[#id='cvv_iframe' and #name='cvv_iframe']")))
Note: As per your code trials the ID of the <iframe> isn't cvv-iframe but cvv_iframe
Here you can find a relevant discussion on Ways to deal with #document under iframe