code: def _calculate_number_trajectories(
      model_inputs: np.ndarray, trajectory_size: int
  ) -> int:
      """Calculate the number of trajectories.
  
      Parameters
      ----------
      model_inputs: np.ndarray
          Matrix of model inputs
      trajectory_size: int
          Number of input points in each trajectory
  
      Returns
      -------
      num_trajectories: int
          Number of trajectories
      """
      num_input_points = model_inputs.shape[0]
      num_trajectories = int(num_input_points / trajectory_size)
  
      return num_trajectories
  
imports: from typing import Dict, List
  import numpy
  from scipy.stats import norm
  from .None import common_args
  from ..util import read_param_file, compute_groups_matrix, ResultDict, _define_problem_with_groups, _compute_delta, _check_groups
label_desc: Use image node_id 9 for calling a global function with example usage: _calculate_number_trajectories(model_inputs, trajectory_size) and returns: num_trajectories