code: def shape(self) -> Shape:
      M = 2 * self.M - 1
      D = 1  # Input size.
      P = 1  # Output size.
      return (M, D, P)
  
imports: import numpy
  import tensorflow
  from check_shapes import Shape
  import gpflow
  from gpflow import covariances
  from gpflow import kullback_leiblers
  from gpflow.base import TensorLike
  from gpflow.ci_utils import reduce_in_tests
  from gpflow.inducing_variables import InducingVariables
  from gpflow.utilities import to_default_float
  import matplotlib.pyplot
  import gpflow.posteriors
label_desc: Use image node_id 3 for calling the FourierFeatures1D obj's underlying member method code with example usage: obj.shape() and returns: M,  D,  P