Issue with figure 3 notebook

[lgatto]

Running the following cell

melted = pd.melt(plotdf, id_vars='index', value_vars=plotdf.columns.tolist())
melted.rename({'variable':'category', 'index':'total_peptides', 'value':'num_proteins'}, axis=1, inplace=True)
melted = melted[melted['num_proteins'].notnull()]
melted.head()

I hit this exception

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-31-eaf8af8ae2ed> in <module>
----> 1 melted = pd.melt(plotdf, id_vars='index', value_vars=plotdf.columns.tolist())
      2 melted.rename({'variable':'category', 'index':'total_peptides', 'value':'num_proteins'}, axis=1, inplace=True)
      3 melted = melted[melted['num_proteins'].notnull()]
      4 melted.head()

~/anaconda3/lib/python3.8/site-packages/pandas/core/reshape/melt.py in melt(frame, id_vars, value_vars, var_name, value_name, col_level, ignore_index)
    134         mdata[col] = np.asanyarray(frame.columns._get_level_values(i)).repeat(N)
    135 
--> 136     result = frame._constructor(mdata, columns=mcolumns)
    137 
    138     if not ignore_index:

~/anaconda3/lib/python3.8/site-packages/pandas/core/frame.py in __init__(self, data, index, columns, dtype, copy)
    466 
    467         elif isinstance(data, dict):
--> 468             mgr = init_dict(data, index, columns, dtype=dtype)
    469         elif isinstance(data, ma.MaskedArray):
    470             import numpy.ma.mrecords as mrecords

~/anaconda3/lib/python3.8/site-packages/pandas/core/internals/construction.py in init_dict(data, index, columns, dtype)
    281             arr if not is_datetime64tz_dtype(arr) else arr.copy() for arr in arrays
    282         ]
--> 283     return arrays_to_mgr(arrays, data_names, index, columns, dtype=dtype)
    284 
    285 

~/anaconda3/lib/python3.8/site-packages/pandas/core/internals/construction.py in arrays_to_mgr(arrays, arr_names, index, columns, dtype, verify_integrity)
     81 
     82         # don't force copy because getting jammed in an ndarray anyway
---> 83         arrays = _homogenize(arrays, index, dtype)
     84 
     85         columns = ensure_index(columns)

~/anaconda3/lib/python3.8/site-packages/pandas/core/internals/construction.py in _homogenize(data, index, dtype)
    349                     val = dict(val)
    350                 val = lib.fast_multiget(val, oindex._values, default=np.nan)
--> 351             val = sanitize_array(
    352                 val, index, dtype=dtype, copy=False, raise_cast_failure=False
    353             )

~/anaconda3/lib/python3.8/site-packages/pandas/core/construction.py in sanitize_array(data, index, dtype, copy, raise_cast_failure)
    494     elif subarr.ndim > 1:
    495         if isinstance(data, np.ndarray):
--> 496             raise Exception("Data must be 1-dimensional")
    497         else:
    498             subarr = com.asarray_tuplesafe(data, dtype=dtype)

Exception: Data must be 1-dimensional

Let me know what additional information you need from me.