Fix the mismatch of the folder structure between NRL v1 and v2

Locally fix the problem of hard-coded string literals in the ObsPy client.py's __init__ method to make it work with NRL v2 folder structure.

nexus/NRLWizard.py

@@ -4,7 +4,10 @@
 Lloyd Carothers
 Qt Wizard for selecting responses from the IRIS NRL
 '''
-
+import inspect
+import ast
+import inspect
+from textwrap import dedent
 from PySide2 import QtCore, QtGui, QtWidgets
 
 from obspy.clients.nrl import NRL
@@ -19,10 +22,15 @@ GAIN = 'gain'
 class NRLWizard(QtWidgets.QWizard):
     def __init__(self, equipment=SENSOR, root=None):
         super().__init__()
-        #Hack for now as NRL(root=None) crashes
+        # Hack for now as NRL(root=None) crashes
         if not root:
             self.nrl = NRL()
         else:
+            # This will change the structure of the NRL class to be
+            # compatible with NRL v2.
+            # The NRL v1 will fail if used as a root path
+            fixes = {"sensors": "sensor", "dataloggers": "datalogger"}
+            NRL.__init__ = self.replace_str(fixes)(NRL.__init__)
             self.nrl = NRL(root=root)
         nrl_root = self.nrl.root
 
@@ -39,6 +47,44 @@ class NRLWizard(QtWidgets.QWizard):
         self.q_and_as = []
         self.addPage(NRLPage(self, self.top))
 
+    def replace_str(self, correction: dict = None):
+        """
+        This function will change the string literal inside a function. This
+        will be used to correct hard-coded string literal inside the __init__
+        function of the NRL class.
+        :param correction: A dictionary that contains target and replacement
+        strings
+        :type correction: dict
+        :return: The function object
+        """
+        def wrapper(func):
+            tree = ast.parse(dedent(inspect.getsource(func)))
+            for key, val in correction.items():
+                tree = self.__fix_str(key, val, tree)
+            ast.fix_missing_locations(tree)
+            scope = {}
+            exec(compile(tree, inspect.getfile(func), "exec"), func.__globals__
+                 , scope)
+            return scope[func.__name__]
+        return wrapper
+
+    def __fix_str(self, target, replacement, tree):
+        """
+        Replace the target string inside the AST tree with the replacement
+        string.
+        :param target:  String to be replaced inside the AST tree
+        :type target: String
+        :param replacement: New replaced string inside the AST tree
+        :type replacement: String
+        :param tree: The AST tree
+        :type tree: AST
+        :return: The modified AST tree
+        """
+        for node in ast.walk(tree):
+            if isinstance(node, ast.Str) and node.s == target:
+                node.s = replacement
+        return tree
+
     def fresh_page(self):
         # remove all pages ahead
         current_id = self.currentId()