Update app.py

app.py

@@ -68,7 +68,7 @@ if sub and file_to_lookat !=[]:
     dirtest=os.path.join(os.path.dirname(SigProfilerMatrixGenerator.__file__),'references/chromosomes/tsb/GRCh37/')+'*txt'
     st.write(dirtest)
     #st.write(sys.path)
-    if refdownload=True:
+    if refdownload==True:
         with st.spinner('downloading hg19 reference'):
             urllib.request.urlretrieve('https://dl.dropboxusercontent.com/s/et97ewsct862x7m/references.zip?dl=0','references.zip')
             with zipfile.ZipFile('references.zip', 'r') as zip_ref: