On_phase_begin missing from LR_Finder

I am attempting to train a structured data model based off the Rossmann notebook. I have created the learner using

m = md.get_learner(emb_szs, len(df.columns)-len(cat_vars),
                   0.04, 1, [1000, 500], [0.001, 0.001], y_range=y_range)
m.lr_find()

but m.lr_find() is giving the following error:

~/fastai/courses/dl1/fastai/model.py in fit(model, data, n_epochs, opt, crit, metrics, callbacks, stepper, swa_model, swa_start, swa_eval_freq, **kwargs)
    109     if not isinstance(data, Iterable): data = [data]
    110     if len(data) == 1: data = data * len(n_epochs)
--> 111     for cb in callbacks: cb.on_phase_begin()
    112     model_stepper = stepper(model, opt.opt if hasattr(opt,'opt') else opt, crit, **kwargs)
    113     ep_vals = collections.OrderedDict()

AttributeError: 'LR_Finder' object has no attribute 'on_phase_begin'

I have tried to debug the error and found that cb (LR_Finder) has on_batch_begin, on_batch_end, on_epoch_end etc etc but no on_phase_begin function.

My data looks like the following:

emb_szs:

[(38, 19),
 (8, 4),
 (2, 1),
 (3, 2),
 (32, 16),
 (7, 4),
 (25, 13),
 (61, 31),
 (61, 31),
 (3, 2),
 (3, 2),
 (3, 2),
 (3, 2),
 (2, 1),
 (2, 1)]

 len(df.columns)
 186

 len(cat_vars)
 15

 y_range
 (0, 11.023686.....)