Doubt in Handling text data

In label encoding, when I am trying to make a new function and equate it with mapping function. I am getting the result as NAN in gender column. the formula i used is dataframe['sex'] = dataframe.sex.map({ 'male' : 0 , 'female': 1}) yet in sex column i am gettimg all the rows labeled as NAN. and in one-hot encoding, when i am using this formula pd.getdummies(dataframe, columns=['region', 'smoker']) i am getting output properly, but instead of 1 and 0 i am getting true or false in each column. pls clarify my doubt