issues_list = [['Does Old Single Line Diagram file, Diagram.xml, Work With New WPS 325 and  older site Elbow Creek and attempting to reuse old single line diagram diagram.xml  software folder structure.rnrnCan new WPSxa0software display older style single line diagrams?'],
 ['Trafo oil outlet temp warming higher than alarm limit',
  'Hi,rnrnPar112002 is used for the trigger limit for compared to Err112001?xa0rnrnLooking at the last 5 months there has only been 3 Err112001 and no Err112013 which could indicate the oil outlet temp is lower and it should be the warning limit being lowered.rnrnxa0rnrnxa0']]

final_result = []

for item in issues_list:
    result = []
    for inner_item in item:
        line = inner_item.replace("-"," ").replace("_"," ").replace("n"," ").replace("r"," ")
        inner_result = []
        for word in line.split(" "):
            nl = ''
            if "http" in word:
                continue
            for l in word:
                if l.isalpha():
                    nl += l
            inner_result.append(nl)
        result.append(" ".join(inner_result))
    final_result.append(result)
print (final_result)

AttributeError
    <ipython-input-4-79c7163de98b> in <module>
          5     result = []
          6     for inner_item in item:
    ----> 7         line = inner_item.replace("-"," ").replace("_"," ").replace("n"," ").replace("r"," ")
          8         inner_result = []
          9         for word in line.split(" "):

    AttributeError: 'NoneType' object has no attribute 'replace'