Method dispatch function for neighborhood selection

Usage

get_neighborhood_signal(coord, signal, method, k = 20, depth = 3, radius = 20)

coord: data.frame - coordinates of assay (barcodes, x, y)
signal: matrix - matrix or sparse matrix containing assay signal for all spatial indices contained in coord
method: character - which method should be use to collect neighborhood - switch matches
k: int - how many nearest neighbors from KNN algorithm
depth: int - graph path depth to define neighborhood 0 = self, 1 = direct neigbors, 2 = neighbors of neighbors, etc
radius: - numeric - radius around center cell

matrix of average signals for each spatial index and its neighborhood.