lmemm_within: lmemm_within
In jflournoy/permediatr:

lmemm_within

lmemm_within(data, y.name, x.name, m_b.name, m_a.name, group.id,
  covariates.y = NULL, covariates.m = NULL, random.a = T,
  random.b = T, random.c_p = T, optimizer = "nloptwrap",
  lmeropts = list())

`y.name`	y variable name.
`x.name`	x variable name (should be within-person centered).
`m_b.name`	mediator variable name (within-person centered for computing b path).
`m_a.name`	mediator variable name (raw for computing a path).
`group.id`	grouping variable for random effects.
`covariates.y`	any covariates to include in regression of y.
`covariates.m`	any covariates to include in regression of m.
`random.a`	include random effect for m on x (a path).
`random.b`	include random effect for y on m (b path).
`random.c_p`	include random effect for y on x (c' path).
`lmeropts`