diff --git a/internal/multipart/component.go b/internal/multipart/component.go
index df4d8bf..0080bd2 100644
--- a/internal/multipart/component.go
+++ b/internal/multipart/component.go
@@ -13,19 +13,19 @@ func (comp *Component) parseHeaders(_raw []byte) error {
 	// 1. Extract lines
 	_lines := strings.Split(string(_raw), "\n")
 	if len(_lines) < 2 {
-		return ErrNoHeader
+		return errNoHeader
 	}
 
 	// 2. trim each line + remove 'Content-Disposition' prefix
 	header := strings.Trim(_lines[0], " \t\r")
 
 	if !strings.HasPrefix(header, "Content-Disposition: form-data;") {
-		return ErrNoHeader
+		return errNoHeader
 	}
 	header = strings.Trim(header[len("Content-Disposition: form-data;"):], " \t\r")
 
 	if len(header) < 1 {
-		return ErrNoHeader
+		return errNoHeader
 	}
 
 	// 3. Extract each key-value pair
diff --git a/internal/multipart/types.go b/internal/multipart/multipart.go
similarity index 52%
rename from internal/multipart/types.go
rename to internal/multipart/multipart.go
index a14fd61..970cca8 100644
--- a/internal/multipart/types.go
+++ b/internal/multipart/multipart.go
@@ -3,19 +3,18 @@ package multipart
 // cerr allows you to create constant "const" error with type boxing.
 type cerr string
 
-// Error implements the error builtin interface.
 func (err cerr) Error() string {
 	return string(err)
 }
 
-// ErrMissingDataName is set when a multipart variable/file has no name="..."
-const ErrMissingDataName = cerr("data has no name")
+// errMissingDataName is set when a multipart variable/file has no name="..."
+const errMissingDataName = cerr("data has no name")
 
-// ErrDataNameConflict is set when a multipart variable/file name is already used
-const ErrDataNameConflict = cerr("data name conflict")
+// errDataNameConflict is set when a multipart variable/file name is already used
+const errDataNameConflict = cerr("data name conflict")
 
-// ErrNoHeader is set when a multipart variable/file has no (valid) header
-const ErrNoHeader = cerr("data has no header")
+// errNoHeader is set when a multipart variable/file has no (valid) header
+const errNoHeader = cerr("data has no header")
 
 // Component represents a multipart variable/file
 type Component struct {
diff --git a/internal/multipart/reader.go b/internal/multipart/reader.go
index affb80a..eaa8449 100644
--- a/internal/multipart/reader.go
+++ b/internal/multipart/reader.go
@@ -71,11 +71,11 @@ func (reader *Reader) Parse() error {
 
 		name := comp.GetHeader("name")
 		if len(name) < 1 {
-			return ErrMissingDataName
+			return errMissingDataName
 		}
 
 		if _, nameUsed := reader.Data[name]; nameUsed {
-			return ErrDataNameConflict
+			return errDataNameConflict
 		}
 
 		reader.Data[name] = comp
diff --git a/internal/multipart/reader_test.go b/internal/multipart/reader_test.go
index 0c4cc02..fa3dfdb 100644
--- a/internal/multipart/reader_test.go
+++ b/internal/multipart/reader_test.go
@@ -196,8 +196,8 @@ func TestNoName(t *testing.T) {
 				return
 			}
 
-			if err = mpr.Parse(); err != ErrMissingDataName {
-				t.Errorf("expected the error <%s>, got <%s>", ErrMissingDataName, err)
+			if err = mpr.Parse(); err != errMissingDataName {
+				t.Errorf("expected the error <%s>, got <%s>", errMissingDataName, err)
 				return
 			}
 		})
@@ -238,8 +238,8 @@ func TestNoHeader(t *testing.T) {
 				return
 			}
 
-			if err = mpr.Parse(); err != ErrNoHeader {
-				t.Errorf("expected the error <%s>, got <%s>", ErrNoHeader, err)
+			if err = mpr.Parse(); err != errNoHeader {
+				t.Errorf("expected the error <%s>, got <%s>", errNoHeader, err)
 				return
 			}
 		})
@@ -274,8 +274,8 @@ facebook.com
 		t.Fatalf("unexpected error <%s>", err)
 	}
 
-	if err = mpr.Parse(); err != ErrDataNameConflict {
-		t.Fatalf("expected the error <%s>, got <%s>", ErrDataNameConflict, err)
+	if err = mpr.Parse(); err != errDataNameConflict {
+		t.Fatalf("expected the error <%s>, got <%s>", errDataNameConflict, err)
 	}
 
 }