import re
regex = r"^SONG\b.*\r?\n((?:(?![A-Z][A-Z ]*$).*\r?\n)*)\s*"
test_str = ("And I lie listening awake? \n"
"SONG \n"
"You are as gold \n"
"The half-opened flowers \n"
"For your face is as fair as rain, \n"
"Yet as rain that lies clear \n"
"Casts light for a shadow. \n"
"AT BAIA \n"
"I should have thought")
print (re.findall(regex, test_str, re.MULTILINE))
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