def contrib_email(contrib_tag):
email = []<EOL>for email_tag in extract_nodes(contrib_tag, "<STR_LIT:email>"):<EOL><INDENT>if email_tag.parent.name != "<STR_LIT>":<EOL><INDENT>email.append(email_tag.text)<EOL><DEDENT><DEDENT>return email if len(email) > <NUM_LIT:0> else None<EOL>
Given a contrib tag, look for an email tag, and
only return the value if it is not inside an aff tag