help?> KM3NeT.make_cherenkov_calculator
  function make_cherenkov_calculator(track_pos, track_dir)

  Returns a function which calculates the arrival time of a Cherenkov photon at a given
  position.

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  function make_cherenkov_calculator(d_closest, t_closest, z_closest, dir_z, t₀)

  Returns a function which calculates the arrival time of a Cherenkov photon at a given
  position.

julia> KM3NeT.make_cherenkov_calculator([0,0,1], [0,0,-1])
ERROR: MethodError: no method matching make_cherenkov_calculator(::Array{Int64,1}, ::Array{Int64,1})
Closest candidates are:
  make_cherenkov_calculator(::Any, ::Any, ::Any, ::Any, ::Any) at /Users/tamasgal/.julia/dev/KM3NeT/src/mc.jl:55
Stacktrace:
 [1] top-level scope at none:0