file.newlines
newlines
If Python was built with the —with-universal-newlines option to
configure (the default) this read-only attribute exists, and for
files opened in universal newline read mode it keeps track of the
types of newlines encountered while reading the file. The values it
can take are '\r', '\n', '\r\n', None (unknown, no newlines
read yet) or a tuple containing all the newline types seen, to
indicate that multiple newline conventions were encountered. For files
not opened in universal newline read mode the value of this attribute
will be None.