class_docstr: Base class for fitness functions
  
  Each fitness function class has the following:
  - fitness(...) : compute fitness function.
     Arguments accepted by fitness must be among [T_k, N_k, a_k, b_k, c_k]
  - prior(N, Ntot) : compute prior on N given a total number of points Ntot
class_docstr_tok: ["Base","class","for","fitness","functions","Each","fitness","function","class","has","the","following",":","-","fitness","(","...",")",":","compute","fitness","function",".","Arguments","accepted","by","fitness","must","be","among","[","T_k",",","N_k",",","a_k",",","b_k",",","c_k","]","-","prior","(","N",",","Ntot",")",":","compute","prior","on","N","given","a","total","number","of","points","Ntot"]
docstr: Check that input is valid
docstr_tok: ["Check","that","input","is","valid"]
code: def validate_input(self, t, x, sigma):
      """Check that input is valid"""
      pass
  
imports: import numpy
  from astroML.utils import deprecated
  from astroML.utils.exceptions import AstroMLDeprecationWarning
label_desc: Use image node_id 2 for calling the FitnessFunc obj's underlying member method code with example usage: obj.validate_input(t, x, sigma) without return types