lxml_complex_text.py

# create a text representation of the element
# etree.tostring() spits out all text, including tags and subtags
text = etree.tostring(element_with_complex_text)

# do the manipulation
text = text.replace("Prince", "Artist formerly known as Prince")

# transform that text back into an lxml element
new_element = etree.fromstring(text)

# get the index of the old element from its parent
parent = element_with_complex_text.getparent()
index = parent.index(element_with_complex_text)

# remove the old element
parent.remove(element_with_complex_text)

# insert the new one
parent.insert(index, new_element)