k: a positive integer number for k-nearest neighbors
kernel_method: a string value, which has to be one of 'triangular', 'uniform', 'epanechnikov', 'quartic', 'gaussian'
adaptive_bandwidth: (optional) TRUE (default) or FALSE: TRUE use adaptive bandwidth calculated using distance of k-nearest neithbors, FALSE use max distance of all observation to their k-nearest neighbors
use_kernel_diagonals: (optional) FALSE (default) or TRUE, apply kernel on the diagonal of weights matrix
power: (optional) The power (or exponent) of a number says how many times to use the number in a multiplication.
is_inverse: (optional) FALSE (default) or TRUE, apply inverse on distance value
is_arc: (optional) FALSE (default) or TRUE, compute arc distance between two observations
is_mile: (optional) TRUE (default) or FALSE, convert distance unit from mile to km.