code: def first(iterable):
      return next(filter(lambda x: x is not None, iterable), None)
  
imports: import unittest
  import textwrap
  from email import policy, message_from_string
  from email.message import EmailMessage, MIMEPart
  from test.test_email import TestEmailBase, parameterize
label_desc: Use image node_id 1 for calling a global function with example usage: first(iterable) and returns: next