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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _find_parameter(self, name_list, create_missing=False, quiet=False):
 """ Tries to find and return the parameter of the specified name. The name should be of the form ['branch1','branch2', 'parametername'] Setting create_missing=True means if it doesn't find a branch it will create one. Setting quiet=True will suppress error messages (for checking) """

        # make a copy so this isn't destructive to the supplied list
        s = list(name_list)

        # if the length is zero, return the root widget
        if len(s)==0: return self._widget

        # the first name must be treated differently because it is
        # the main widget, not a branch
        r = self._clean_up_name(s.pop(0))

        # search for the root name
        result = self._widget.findItems(r, _g.QtCore.Qt.MatchCaseSensitive | _g.QtCore.Qt.MatchFixedString)

        # if it pooped and we're not supposed to create it, quit
        if len(result) == 0 and not create_missing:
            if not quiet: self.print_message("ERROR: Could not find '"+r+"'")
            return None

        # otherwise use the first value
        elif len(result): x = result[0].param

        # otherwise, if there are more names in the list,
        # create the branch and keep going
        else:
            x = _g.parametertree.Parameter.create(name=r, type='group', children=[])
            self._widget.addParameters(x)

        # loop over the remaining names, and use a different search method
        for n in s:

            # first clean up
            n = self._clean_up_name(n)

            # try to search for the name
            try: x = x.param(n)

            # name doesn't exist
            except:

                # if we're supposed to, create the new branch
                if create_missing: x = x.addChild(_g.parametertree.Parameter.create(name=n, type='group', children=[]))

                # otherwise poop out
                else:
                    if not quiet: self.print_message("ERROR: Could not find '"+n+"' in '"+x.name()+"'")
                    return None

        # return the last one we found / created.
        return x