exists(path) {
    path = coercePath(path);

    if (arguments.length > 1)
      path = arrayFrom(arguments);

    return this._get(path).exists;
  }
Method used to check whether a certain path exists in the tree starting
from the current cursor.

Arity (1):
@param  {path}   path           - Path to check in the tree.

Arity (2):
@param {..step}  path           - Path to check in the tree.

@return {boolean}               - Does the given path exists?