diff --git a/src/cenreg/distribution/cdf.py b/src/cenreg/distribution/cdf.py
index db888e1..ee43381 100644
--- a/src/cenreg/distribution/cdf.py
+++ b/src/cenreg/distribution/cdf.py
@@ -1,3 +1,5 @@
+from typing import Literal
+
 import numpy as np
 
 from cenreg.distribution.interpolate import linear_interpolation
@@ -13,7 +15,7 @@ def __init__(
         b: np.ndarray,
         p: np.ndarray | None = None,
         cum_p: np.ndarray | None = None,
-        interpolate: str = "linear",
+        interpolate: Literal["linear", "left", "right"] = "linear",
         confidence_interval: np.ndarray | None = None,
     ):
         """
@@ -31,7 +33,7 @@ def __init__(
             Cumulative probability distribution.
             cum_p must be one-dimensional or two-dimensional.
             If both p and cum_p are given, cum_p is used.
-        interpolate : str
+        interpolate :  Literal["linear", "left", "right"]
             'linear', 'left', or 'right' indicating the interpolation method.
             If 'linear' is set, linear interpolation is used.
             If 'left' is set, the CDF value at the left edge of each bin is used.
@@ -73,7 +75,7 @@ def __init__(
         self.interpolate = interpolate
         self.confidence_interval = confidence_interval
 
-    def cdf(self, y: float | np.ndarray):
+    def cdf(self, y: int | float | np.ndarray):
         """
         Cumulative distribution function (i.e., inverse of quantile function).
 
@@ -87,6 +89,8 @@ def cdf(self, y: float | np.ndarray):
         cum_p : np.ndarray
             CDF values for each value in y.
         """
+        if isinstance(y, int | float):
+            y = np.array([y], dtype=float)
 
         if self.cum_p.ndim == 1:
             assert y.ndim == 1
@@ -95,8 +99,6 @@ def cdf(self, y: float | np.ndarray):
         else:
             raise ValueError("cum_p must be one-dimensional or two-dimensional.")
 
-        if isinstance(y, float):
-            y = np.array([y])
         if self.cum_p.ndim == 2 and y.ndim == 1:
             y = np.tile(y, (self.cum_p.shape[0], 1))
 
@@ -154,8 +156,8 @@ def icdf(self, quantiles: float | np.ndarray) -> np.ndarray:
             Compute inverse CDF values for each value in quantiles.
         """
 
-        if isinstance(quantiles, float):
-            quantiles = np.array([quantiles])
+        if isinstance(quantiles, int | float):
+            quantiles = np.array([quantiles], dtype=float)
         if np.any(quantiles < 0.0):
             raise ValueError("quantiles must be non-negative.")
         if np.any(quantiles > 1.0):
diff --git a/src/cenreg/distribution/quantile.py b/src/cenreg/distribution/quantile.py
index b2101f7..e053433 100644
--- a/src/cenreg/distribution/quantile.py
+++ b/src/cenreg/distribution/quantile.py
@@ -61,8 +61,8 @@ def cdf(self, y: float | np.ndarray):
             CDF values for each value in y.
             Array shape is equal to the shape of y.
         """
-        if isinstance(y, float):
-            y = np.array([y])
+        if isinstance(y, int | float):
+            y = np.array([y], dtype=float)
 
         if self.interpolate == "linear":
             # linear interpolation implementation
@@ -97,7 +97,7 @@ def icdf(self, quantiles: float | np.ndarray) -> np.ndarray:
             Array shape is equal to the shape of quantiles.
         """
 
-        if isinstance(quantiles, float):
+        if isinstance(quantiles, int | float):
             quantiles = np.array([quantiles])
         if np.any(quantiles < 0.0):
             raise ValueError("quantiles must be non-negative.")
diff --git a/src/cenreg/model/nonparametric.py b/src/cenreg/model/nonparametric.py
index 0f3b349..58767e2 100644
--- a/src/cenreg/model/nonparametric.py
+++ b/src/cenreg/model/nonparametric.py
@@ -205,8 +205,8 @@ def kaplan_meier_estimator(
     else:
         survival_rates = survival_rates[:-1]
     dist = CumulativeDist(b=b, cum_p=1.0 - survival_rates, interpolate="right")
-    dist.alive = num_alive
-    dist.dead = num_death
+    # dist.alive = num_alive
+    # dist.dead = num_death
     return dist
 
 
diff --git a/src/cenreg/pytorch/cjd2F.py b/src/cenreg/pytorch/cjd2F.py
index 2a4e0e1..b487fc3 100644
--- a/src/cenreg/pytorch/cjd2F.py
+++ b/src/cenreg/pytorch/cjd2F.py
@@ -20,13 +20,14 @@ def __init__(
         optimizer=None,
     ):
         super().__init__()
-        assert len(init_f.shape) == 3
+        if init_f is not None:
+            assert len(init_f.shape) == 3
         assert len(jd_pred.shape) == 3
 
         self.jd_pred = torch.tensor(jd_pred, dtype=torch.float32).detach()
         self.focal_risk = focal_risk
         self.fc = nn.Linear(1, jd_pred.size, bias=False)
-        self.shape = init_f.shape
+        self.shape = init_f.shape if init_f is not None else jd_pred.shape
         self.copula = copula
         self.learning_rate = learning_rate
         if init_f is not None:
@@ -61,7 +62,7 @@ def _copula_sum_sub(
         self,
         F_pred: torch.Tensor,
         c,
-        idx_list: list[int],
+        idx_list: list[list[int]],
         i: int,
         k: int,
         idx_list_use_Ft: Sequence[int],
@@ -187,6 +188,7 @@ def minimize_mse(model, num_epochs: int) -> np.ndarray:
     F_pred: estimated CDF.
         np.ndarray of shape [batch_size, num_risks, num_bin_predictions+1]
     """
+    assert num_epochs > 0
 
     best_epoch = -1
     best_loss = float("inf")
@@ -235,6 +237,7 @@ def minimize_mse(model, num_epochs: int) -> np.ndarray:
             loss.backward()
             optimizer.step()
 
+    assert path is not None
     checkpoint = torch.load(path)
     model.load_state_dict(checkpoint["model_state_dict"])
     model.eval()