code: def dspmt(t):
      """SPM canonical HRF derivative, HRF derivative values for time values `t`
  
      This is the canonical HRF derivative function as used in SPM.
  
      It is the numerical difference of the HRF sampled at time `t` minus the
      values sampled at time `t` -1
      """
      t = np.asarray(t)
      return spmt(t) - spmt(t - 1)
  
file_path: nipy/nipy/modalities/fmri/hrf.py
imports: from functools import partial
  import numpy
  import scipy.stats
  import sympy
  from sympy.utilities.lambdify import implemented_function
  from .utils import T, lambdify_t
label_desc: Use image node_id 7 for calling a global function with example usage: dspmt(t) and returns: unknown