code: def dataframe_to_json(df, obj):
      if df is None:
          return None
      else:
          # Replacing NaNs with None as it's not valid JSON
          cleandf = df.fillna(np.nan).replace([np.nan], [None])
          return cleandf.to_dict(orient="records")
  
imports: from traitlets import TraitError, TraitType
  import numpy
  import pandas
  import warnings
  import datetime
  import six
label_desc: Use image node_id 10 for calling a global function with example usage: dataframe_to_json(df, obj) and returns: None, cleandf