arcgis desktop - Changing second line text using ArcPy?

I work with several maps with this text:

and i try to change the second line only into "landUse" by using this code:

import arcpy
from arcpy import env

env.workspace = r"G:\desktop\Project"
for num, mxdname in enumerate((arcpy.ListFiles("*.mxd")),start = 1):
    print '\n',num,mxdname
    mxd = arcpy.mapping.MapDocument(
    r"G:\desktop\Project\\" + mxdname)
    for elm in arcpy.mapping.ListLayoutElements(mxd, "TEXT_ELEMENT"):
        elm.text = elm.text.replace(u'aaa'[1], u'landUse')

    mxd.save()
del mxd

when i run it i get this unwanted result:

whereas i want this result:

i didn't find an answer in Changing part of text element using ArcPy?

Answer

Try replacing both the newline and 'aaa':

.replace('\naaa', "\nTEXT_ELEMENT")