title: Designing an FIR notch filter with python
body: <p>I am writing some code with Python using the scipy.signal library to filter electromagnetic data that is mixed with various undesirable signatures that I want to filter out.  For example, I have power line harmonics at various frequencies (i.e. 60, 120 Hz, etc....) with a width of only a few Hz that I would like to remove from the data using a notch filter.  Is there already an existing function in python where I can merely inform the code how many data points i wish to use for the filter, the center-line frequency that I wish to remove and the width of the transition band or do I need to design a filter from scratch?  If it is the latter I would greatly appreciate an example of notch filter design in Python to include window implementation to minimize aliasing.</p>