code: def compose(x: OnGrid, *, params=None):
      r"""Maps the given function over the pytree of parameters
      of the `Field`.
  
      """
  
      def decorator(fun):
          return x.replace_params(fun(x.params))
  
      return decorator
  
imports: from typing import List
  import numpy
  from jax import numpy
  from jaxdf.conv import reflection_conv
  from jaxdf.core import operator
  from jaxdf.discretization import Continuous, FiniteDifferences, FourierSeries, OnGrid
  from jaxdf.operators.differential import get_fd_coefficients
label_desc: Use image node_id 3 for calling a global function with example usage: compose(x) and returns: decorator, x