Solution
list = Lines.query.all()
for s in list:
add += str(s.title) + '
'
list = Lines.query.all()
for s in list:
add += '{}
'.format(str(s.title))
list = Lines.query.all()
for s in list:
add += f"{s.title}
"
list = Lines.query.all()
for s in list:
add += str(s.title) + '
'
list = Lines.query.all()
for s in list:
add += '{}
'.format(str(s.title))
list = Lines.query.all()
for s in list:
add += f"{s.title}
"