diff --git a/gnss_lib_py/parsers/clk.py b/gnss_lib_py/parsers/clk.py
index 10fb8ba6..963bf0f3 100644
--- a/gnss_lib_py/parsers/clk.py
+++ b/gnss_lib_py/parsers/clk.py
@@ -94,7 +94,8 @@ def __init__(self, input_paths):
         self["b_sv_m"] = b_sv_m
 
     def interpolate_clk(self, navdata, window=6, verbose=False):
-        """Interpolate clock data from clk file.
+        """Interpolate clock data from clk file, adding inplace to given
+        NavData instance.
 
         Parameters
         ----------
@@ -136,7 +137,7 @@ def interpolate_clk(self, navdata, window=6, verbose=False):
                 b_sv_m = np.zeros(len(navdata_id))
                 b_dot_sv_mps = np.zeros(len(navdata_id))
 
-                # iterate through needed polynoials so don't repeat fit
+                # iterate through needed polynomials so don't repeat fit
                 insert_indexes = np.searchsorted(x_data,navdata_id_gps_millis)
                 for insert_index in np.unique(insert_indexes):
                     max_index = min(len(clk_id)-1,insert_index+int(window/2))
@@ -159,4 +160,4 @@ def interpolate_clk(self, navdata, window=6, verbose=False):
 
                 row_idx = navdata.argwhere("gnss_sv_id",gnss_sv_id)
                 navdata["b_sv_m",row_idx] = b_sv_m
-                navdata["b_dot_sv_mps",row_idx] = b_dot_sv_mps
+                navdata["b_dot  _sv_mps",row_idx] = b_dot_sv_mps
diff --git a/gnss_lib_py/parsers/sp3.py b/gnss_lib_py/parsers/sp3.py
index 99de481e..a6c4a307 100644
--- a/gnss_lib_py/parsers/sp3.py
+++ b/gnss_lib_py/parsers/sp3.py
@@ -47,7 +47,6 @@ def __init__(self, input_paths):
             input_paths = [input_paths]
 
         gps_millis = []
-        unix_millis = []
         gnss_sv_ids = []
         gnss_id = []
         sv_id = []
@@ -105,7 +104,8 @@ def __init__(self, input_paths):
         self["z_sv_m"] = z_sv_m
 
     def interpolate_sp3(self, navdata, window=6, verbose=False):
-        """Interpolate ECEF position data from sp3 file.
+        """Interpolate ECEF position data from sp3 file, inplace to
+        given navdata instance.
 
         Parameters
         ----------
@@ -148,7 +148,7 @@ def interpolate_sp3(self, navdata, window=6, verbose=False):
 
                 xyz_sv_m = np.zeros((6,len(navdata_id)))
 
-                # iterate through needed polynoials so don't repeat fit
+                # iterate through needed polynomials so don't repeat fit
                 insert_indexes = np.searchsorted(x_data,navdata_id_gps_millis)
                 for insert_index in np.unique(insert_indexes):
                     max_index = min(len(sp3_id)-1,insert_index+int(window/2))