What does the residue theorem say about a closed curve curve as shown in this figure: figure
It seems to me that this curve self intersect at origin.
It's related to the Wick rotation and I can't close the $[-\infty, \infty]$ contour in a proper way so that the residues inside are zero, please see link for description of poles and contour.
Thanks for your answers :)
Split the contour into 2 contours, each a simple closed curve enclosing an arc within a quadrant of the complex plane.