give information on files which could not be read and thus not be attended to the waveform container

pylot/core/read/data.py

@@ -134,13 +134,28 @@ class Data(object):
         self.dirty = False
 
     def appendWFData(self, fnames):
+
         if self.dirty is not False:
             self.resetWFData()
+
+        assert isinstance(fnames, list), "input parameter 'fnames' is " \
+                                         "supposed to be of type 'list' " \
+                                         "but is actually".format(type(
+            fnames))
+
+        warnmsg = ''
         for fname in fnames:
             try:
                 self.wfdata += read(fname)
             except TypeError:
+                try:
                     self.wfdata += read(fname, format='GSE2')
+                except Exception:
+                    warnmsg += '{0}\n'.format(fname)
+        if warnmsg:
+            warnmsg = 'WARNING: unable to read\n' + warnmsg
+            print warnmsg
+
 
     def getWFData(self):
         return self.wfdata