Test if children tag exists in beautifulsoup

if tag.find('child_tag_name'):

The simplest way to find if a child tag exists is simply

childTag = xml.find('childTag')
if childTag:
    # do stuff

---

More specifically to OP's question:

If you don't know the structure of the XML doc, you can use the .find() method of the soup. Something like this:

with open("file1.xml",'r') as data, open("file2.xml",'r') as data2:
    xml = BeautifulSoup(data.read())
    xml2 = BeautifulSoup(data2.read())

    hasAttrBs = xml.find("myId")
    hasAttrBs2 = xml2.find("myId")

If you do know the structure, you can get the desired element by accessing the tag name as an attribute like this xml.document.subdoc.myid. So the whole thing would go something like this:

with open("file1.xml",'r') as data, open("file2.xml",'r') as data2:
    xml = BeautifulSoup(data.read())
    xml2 = BeautifulSoup(data2.read())

    hasAttrBs = xml.document.subdoc.myid
    hasAttrBs2 = xml2.document.subdoc.myid
    print hasAttrBs
    print hasAttrBs2

Prints

<myid>1</myid>
None

you can handle it like this:

for child in xml.document.subdoc.children:
    if 'myId' == child.name:
       return True

Here's an example to check if h2 tag exists in an Instagram URL. Hope you find it useful:

import datetime
import urllib
import requests
from bs4 import BeautifulSoup

instagram_url = 'https://www.instagram.com/p/BHijrYFgX2v/?taken-by=findingmero'
html_source = requests.get(instagram_url).text
soup = BeautifulSoup(html_source, "lxml")

if not soup.find('h2'):
    print("didn't find h2")