Problem In calling a Function from another python file of project

[ichabod801]

Now can any one please help me in getting out of this.

Not with what you've given us. We need more information about Digital_Filter. Is it small enough that you can post it here? The question is really how apply_filter is defined in the file. If it is defined conditionally or within another function or class, that could be why the import is not seeing it. Also check to make sure the path given in the error is the path to the correct file.