Change interface to sendmail: if the destination address is a string instead of a list, turn it into a list containing that string.  This avoids an apparently common newbie mistake -- passing in a single string for the destination and have it treated as a sequence of characters.
Change interface to sendmail: if the destination address is a string
instead of a list, turn it into a list containing that string.  This
avoids an apparently common newbie mistake -- passing in a single
string for the destination and have it treated as a sequence of
characters.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator